To avoid the ramblings, you can jump to the list of sans serif typefaces with a stemmed capital I.
Just clarifying a common misconception. Times New Roman and Verdana are typefaces, not fonts. In the context of font design, the word “font” involves typeface, such as Verdana, size, such as 12pt, and style, which could be regular, bold, italic or bold/italic. In other contexts, such as specifying character appearance in a word processing package, font might also be regarded as including text colour, background colour and whether any modifiers such as underline, strikethrough or rotation apply.
If you choose to buy extras for your computer, you will be buying fonts rather than a typeface. It might be marketed as the “Verdana Font”, but what you buy is a range of fonts in many different sizes and styles, all using the Verdana typeface. This marketing practice might be the source of the confusion. Of course these days operating systems come with a large range of fonts and there are also open source fonts that can be downloaded free. Probably the only people who buy extra fonts these days are professional graphic designers.
I find typeface design fascinating and irritating. Apparently typeface designers are forever battling to balance readability and consistency, a battle which I utterly fail to understand.
To be readable, the typeface designer has to ensure that no two glyphs look too similar. For example, this means trying to make the lower case “l” (ell) looks different from the upper case “I” (aye, or maybe eye).
But if they try to maximise the differences in appearance between all the glyphs in their typeface, then at first glance, a page of text written in their typeface is alleged to appear chaotic, inconsistent or downright ugly. Too avoid this effect, they aim for consistency, which means making the glyphs in their typeface share similar features, an aim completely at odds with readability.
What I don't get is this obsession with the at-first-glance impression of the page. After I've been reading a book for a minute or two, I've adjusted to the overall impression of the page and don't notice it any more. By that point, all that matters to me is the readability of the individual glyphs. Sure - maybe the at-first-glance thing has some importance if you're printing an invitation to a ball, but for anything beyond 100 words, who cares?
It reminds me of the aerosol cans of “new car smell”. Car dealers use these to ensure the cars in their showroom don't smell like a hundred previous customers tried sitting in their car before you did. Some dealers even use it in their recent model used cars, to try give the impression that the car was used sparingly, a notion that goes out the window as soon as you read the odometer. The thing is, while the human nose does a good job of detecting changes in smells, fatigue sets in quickly, so by the time you read the odometer, you probably won't be noticing the new car smell anymore.
I once watched a video where a couple of typeface designers were explain how they designed a “hyperlegible” typeface for vision-impaired readers. They explained the battle of balancing readability and consistency. While their explanation deserves high praise for its clarity, it left me wondering how many vision-impaired people they consulted with, because when you're struggling to differentiate between two similar looking characters on a page, you don't care in the slightest about whether an overall glance at the whole page leaves you with the impression of chaos or beauty. Some vision impaired users won't ever have an overall impression of the page since they can't focus on that large an area.
I once lost an argument with a publisher about the typeface used in a book I wrote. Headings were rendered in a sans serif typeface in which the upper case “I” (aye) and lower case “l” (ell) were identical. One of the headings in the book was “Ill Health Insurance”. This meant the word “Ill” appeared as 3 identical line segments. Even though I'd written the heading myself, when I first saw it in this ghastly font, I had trouble reading it. My brain wouldn't make sense of it as a word and wondered whether it was supposed to be the Roman numeral for 3. I pointed this out to my editor, but the response was essentially “It's an unfortunate heading, but this font is our house style and we cannot change it”. I reordered a few sentences so they contained the word “ill” rather than starting with the capitalised “Ill”, but I was stuck with the confusing heading.
Anyway, that's enough rambling to explain why I am forever on the lookout for good sans serif typefaces that have a capital “I” with stems, thus ensuring they are distinguishable from the lower case “l” and the number “1”. Here's my results to date.
Apart from the Display version having the letters packed slightly more closely together, I'm struggling to spot any differences between these two.
The Noto family contains well over 100 different typefaces. They were designed to support a large range of languages, so they includes typefaces with names like Noto Sans Thai, Noto Sans Tibetan and Noto Sans Myanmar. The odd thing is that while the Noto Sans and Noto Sans Display typefaces have a stemmed capital I, the variants designed to support particular languages do not.
If you're a fan of open source software, you'll probably have a good selection of Noto typefaces already installed. They come with the default installation of many versions of linux and also with the popular LibreOffice application. However I hear that in both those sceanarios it might be possible for Noto to be missing if you tweaked the installation settings to minimise disk space usage by excluding internationalisation options. These typefaces were commisioned by Google but released into the wild under a free open license. If you don't have them, you can get them here, but being a Google site you may sometimes find yourself blocked if you use TOR browser to preserve your anonymity.
If you use TOR browser on Linux, you've got another problem. TOR apparently contains a list of typefaces it will allow web pages to use, and will block all other typefaces, replacing them by a typeface from its acceptable list. While the list of acceptable typefaces does include several language specific Noto fonts, none of these have the stemmed capital I. As far as I can ascertain, the only sans serif typefaces with a stemmed capital I that TOR allows are Verdana and Tahoma, and if you're on a Linux system you probably don't have either of those fonts. I haven't found a solution to this. (Well, one “solution” is to see if your Linux repository has the ttf-mscorefonts-installer package that can install fonts using the Verdana typeface, but if you've gone to the trouble of using Linux, why would you want to install a package that requires you to agree to a Microsoft EULA?)
I'm listing Loma because it does meet the criteria for this page, but I'm not a fan. It reads well in normal weight, but when used in Bold form the kerning is poor, causing some letter combinations to run togetter and making it hard to read. Since I always use San Serif bold for headings, this makes it problematic for me.
The font was created by NECTEC, Thailand’s National Electronics and Computer Technology Center, who released it into the wild under a free license. This typeface was designed to provide several alphabets used by Thai dialects, but also comes with all the glyphs for English. It is packaged with some versions of Linux, but whether you have it pre-installed versus needing to install it from the repository may depend on whether you fiddled with the language options during installation. If you aren't on Linux, you probably don't have it by default, though it would be worth opening the language options in your operating system and seeing if choosing Thai gives you an option to install it. If that fails, it becomes messier. Here is a site that claims to provide the font, but it's not clear to me who is running that site, so use at your own risk. I would have preferred to supply a link to a more official site, such as NECTEC, but couldn't find it there. However, I only understand the English sections of that site - you might have more success if you can read the Thai pages.
One problem with Loma typeface is that there is a more recent conflicting Loma. This needn't stop you using NECTEC's Loma in your own documents. However, if you are building web pages and specify Loma font in your CSS font stack, your web page may look odd on computers that have the other Loma installed, since it is a “vintage style stamp font”. (There's that point of confusion again. A “CSS font stack” is a list of typefaces, not fonts.)
Proprietory. Verdana is almost certainly installed on any Windows system computer made this century, and usually absent from non-Windows systems. Verdana was so popular that there are some open source alternatives that are alleged to be based on or inspired by Verdana, but apparently those designers weren't inspired by Verdana's stemmed capital I, since they removed the stems. There's even a font called Veranda which claims to be a drop-in replacement for Verdana. How is it a drop-in replacement if the capital I isn't the same width, due to the stems being removed?
Proprietory. From the same designer as Verdana, billed as similar to Verdana but slightly thinner. Installed on many Windows systems, but more importantly, often available on Apple computers that don't have Verdana, so this is a good one for web designers to include in a CSS font stack.
You web designers already know how to peek at my style sheets, but to save you the trouble, here's my CSS font stack of sans serif fonts.
font-family: "Noto Sans", Verdana, Tahoma, sans-serif ;
Most Linux system will use Noto Sans, as will most systems with LibreOffice installed. Of the non-Linux systems without LibreOffice office, most windows systems will use Verdana and most Apple systems will use Tahoma. (As mentioned above, TOR browser on Linux will fail to display Noto Sans due to whitelist issues and will probably fall through to a default sans-serif font of Arima, which does not have a stemmed capital I.)
Trying to predict the font behaviour of browsers on mobile phones is a mug's game that I will not enter into.