(descriptions in the tooltips if you hover on them)
(plus one secret badge that hasn't been awarded yet)
That's a fair few, but I'd like to see more. In the answers here, propose a badge (or badges), along with its tier (bronze/silver/gold) and requirements that you'd like to see added to the challenge badges.
At some as-yet-undefined threshold of community approval through votes, I'll add the badges to the generator.