I also made maps for Half-Life and Counter Strike. I had them uploaded to my Geocities page but have since lost them. Never found my webpage (cool_kirby77) in the various Geocities archives either.
Those creations only exist in my memory now (and maybe others who played them at the time). Sometimes I wonder if what I created was really as spectacular as I thought it was.
The only thing I have saved from my childhood is a single-player map I made for Medal of Honor: Allied Assault. The only reason I have it is because I searched years later, and apparently someone took many of the custom maps from the community over the years and uploaded them to some German website. So I could download the .bsp, but the original .map was lost so I couldn't make changes if I wanted to.
I downloaded the map, installed MOHAA and recorded a playthrough so I'd never have to worry about losing it again: https://www.youtube.com/watch?v=EhPK__EgsC4
I made that map because I hated how in MOHAA (and most other games like Quake, Soldier of Fortune etc) you were 1 man vs a million. I wanted an FPS where you actually had (useful) allies that helped you throughout the game. Not much longer after I released the map, a number of employees left "2015" (the company that made MOHAA) and started a new company, Infinity Ward. Their first game, Call of Duty, was very similar to MOHAA, but you were actually surrounded by friendly troops that fought with you!
So I like to think that my map was a pioneer that launched a multi-million dollar franchise and cultural phenomenon ;)