megrar
Kyousouka
A well-made font for lettering comics will include contextual variants (for example, so that in "MILLING", the LL isn't made of identical Ls, and even the two Is might be different because they're so close to each other), but this is very rare, especially among free fonts. If you are so inclined, you could create a font of your own handlettering with this type of variation. It would be a time investment up front, but it might save you time later since you won't have to print lettering guides or worry about neatness.
this suggestion of contextual variants sounds ******** AMAZING. how do you do this?
Comicraft's fonts sometimes provide variants in the form of ligatures consisting of lower- and uppercase versions of each letter (if you haven't noticed them, you might have Ligatures turned off so check for that, but perhaps your specific fonts lack them entirely), and/or you can use the lower/upper case letters in a mixture by hand. That's not as good as real alternatives, especially for fonts that aren't all-caps. They also use the lamest possible way to do the serif-I (it's just a capital I), which means I can't have variants of its own.
OpenType supports better ways.
It has a contextual substitution feature (a couple of different versions of it for different situations). It can be very powerful and can handle a large number of variants. There are other ways to achieve variants (including some that are not context-based), but I haven't looked into them in detail. Contextual substitution does well enough for me and I'd rather spend my time drawing comics.
I use FontForge for my font work, it's free and supports every feature of OpenType.
If you just want to modify an existing font, you can do that; Fontforge can import most existing formats (although I think it can get a little weird with some poorly defined fonts).
Edit:
I made a tutorial about one of the many ways to add letter variants to a font in FontForge. It's for double letters, which is the case in which digital perfection is most obvious. The other cases (like proximity variants) are similar, but done By Classes (since we need a short way to say "X followed by anything-but-X followed by X"
).
The description has links to the official tutorial, so I edited my post above to remove them.
Edit2: I also added a part 2, about proximity variants.