There is a straightforward query provided by Michael Mrozek with SEDE
There are 607 tag pairs on Stack Overflow which differ by only a hyphen!!
SELECT a.TagName AS First, b.TagName AS Second FROM Tags AS a, Tags AS b WHERE a.Id < b.Id AND REPLACE(a.TagName, '-', '') = REPLACE(b.TagName, '-', '');
Call to Arms
After upvoting his awesomeness, please make synonym suggestions. Note that this data is a month old, so -- for example -- stackoverflow and stack-overflow were already proposed, but still need votes!!
And, lest you think this is on a problem on Stack Overflow, Programmers has six tag pairs and I'm sure there are plenty others out there -- Super User has 29. Server Fault has 55. Let's get those badges!
And also Plurals
After learning a bit more SQL, I've also constructed a query for tags which differ by only ending in 's' or 'es'. There are currently 614 tag pairs on Stack Overflow which fit this criterion. Now it does incorrectly catch (css, c) as well as (aes, a), but it certainly has plenty of synonyms to suggest!!