We now can use up to 35 characters in tags! Hooray! This means that now we can rename some awkward tags that weren't able to be created well because of the 25 character limit. However, as @AnkitSharma points out, creating a meta post for each tag that should be renamed would be silly. Instead, here's a master list. Please edit the community wiki answer below with the list of tags that should be renamed now that we can have more characters. Please link to the appropriate meta question if one already exists.
Note: this doesn't have to mess up the front page. Tag renames can be done almost silently by mods (although one bump may be required per rename).