I have 20 in my bag but I don't throw them all regularly. The number of each mold changes periodically as I loose and replace discs, but this is about normal:
5 Wizards. 1 putting, 1 for when I need a softer one, 1 approach and 2 (new and beat) for driving. I usually use 3 per round (putter, approach and one driving).
2 Rocs. 1 KC Pro and 1 DX. They're both fairly new so I'm beating them in. The DX is noticeably more overstable than the KC Pro.
3 DX Gazelles. Different stages of wear.
3 Teebirds. 2 DX, 1 Star. I have one nice and beat DX and I just lost (aka forgot to get after a throw) a sorta beat one so I get to replace it with a new one. The Star is apparently there for show because I never throw it. It seems like I'm always just trying to beat in another DX.
1 X Avenger. It's my distance driver for now but I have enough distance drivers that I probably will replace it with something else when it either gets too beat or I loose it (more likely). It's basically for longer Teebird shots or when there's a bit more wind than I like for a beat Teebird.
1 SOLF. Long hyzers/headwind distance. I'm usually happy after I throw it.
3 Spirits. 1 newish E, 1 "tuned" E that's high speed understable and I almost never throw and 1 beat S that's not all that different from my SOLF. I don't use the S very much now that I have the SOLF.
1 Star Destroyer. Token Star Wars reference disc. I'll use it for sidearm throws every once in a while, but only because it's there. I could drop it and it wouldn't affect my normal game at all.
1 ESP Nuke. I found it a couple weeks ago and keep forgetting to take it out or throw it to see what it does.
So, if you look at what I throw vs. what's in there just to take up space:
Throw - 4 Wizards, 2 Rocs, 3 Gazelles, 2 Teebirds, 1 Avenger, 1 SOLF, 1 Spirit.
Show - 1 Wizard (custom stamped for our wedding), 1 Teebird, 2 Spirits (though they kind of act as backups for the Avenger and SOLF...at least that's how I justify carrying them), 1 Destroyer, 1 Nuke.