A lot of the time, even on pleasant-looking, modern websites or images, letters with Esperanto diacritics stand out from the rest due to the font chosen. Which fonts support the ĉapeloj?
Here is a list that someone made of fonts on fontlibrary.org that support Esperanto.
A good general-purpose free font that has good support for a wide range of languages including Esperanto is Google’s Noto.
There is also this rather beautiful font:
I think most modern tools for creating fonts can just automatically generate the letters with hats because the font author provides a drawing for the appearance of the circumflex and also specifies the position where diacritics should appear for each letter. This works well for most of the Esperanto letters because they already exist with different diacritics in other languages. However I find that the “ĥ“ often ends up with an ugly-looking position because the letter is unusually tall and I imagine the font authors don’t give it much thought.
If you have the source code for a font it is relatively easy to manually add the hats to the Esperanto letters using the free FontForge program. I was able to do this without any trouble despite not having any typography experience when I helped typeset an Esperanto translation of a book that was using a particular stylised font.
I don't know of any widely used fonts that don't have all the letters of Esperanto. There are fancy fonts designed for a limited set of letters or symbols or just for certain languages (Inuktitut, Sanskrit or English, say), but I have never used anything of the kind. If your computer supports Adobe Flash, you can test all your own fonts on this page:
Just write a suitable string of letters (abc ĈĜĤĴŜŬ ĉĝĥĵŝŭ) in the Sample text box.
There are more than 100 ĉapelo-capable fonts in my desktop computer and I have never needed any additional Esperanto fonts.
I've seen pages where the Esperanto letters stand out, but I think this is caused by bad html (too strict font definition) or bad rendering in your browser.
I looked through all my fonts, and though many support Esperanto, most have the circumflex for the h centered on the letter rather than centred on the riser. A few fonts and families that do it right were:
Adobe Ming Std, Alipe Script, Anivers, Constantina, Fertigo Pro, Franklin Gothic, FreeSans, Futura, Gnuolane, Grenale, iA Writer Duospace, Kenyan Coffee, Kozuka Gothic, Kozuka Mincho, LTC Village, Pekora, Segoe, Sitka, Solomon, Source Sans, True North Script, URW DIN and Yu Gothic.
Some of these are free, and some are paid for, but I thought a list like this might still be helpful to some in finding a suitable font.