I don't really have a 'collection' as most people on thin site now seem to descried/think of it...
I more have a 'hord,' which has more accumulated rather than been collected over the years.
I have sold a few things... mostly zx81, spectrum (including an Interface1, interface 2, and a micro-drive),, BBC or Atari 8bit related. Some of it I sort of regret, as they have become rarer.
As far as I can remember my current hoard roughly consists of the following 'retro stuff':
A Telequipment S61 oscilloscope. (and another slightly younger scope I can't remember the make of)
A Telling Colourstars TV game with cartridges.
A Vectrex, all original games + programming cartridges.
Two VIC-20s one boxed, one not booting to basic - but plays cartridges!? 17 cartridges and 20+ tapes.
A BBC Cub monitor and double cumana 5.25" floppy disk drive (BBC B broke and was chucked)
Loads of 8bit Atari games, 5 or 6 catradges loads of tapes easily 50+
The second type of master system with around 20+ games
Two mega-drives (second version) one megaCD, one light gun (3D goggles were lost) 50-60+ games.
One Atari Lynx, no games.
Two Sage Game Gear, 10+ games, and the TV adapter.
Two game-boy colour 10+ games
A SNES with 5 games.
Amiga 600, with various upgrades.
A psiona and psionc and Senna - got Horace in the Mystic Woods on a cartridge along with some puzzle type games
A Saturn with 8 games.
A Game.com - just the starter pack games.
A Nintendo 64 with 5 games.
Three Dreamcasts, one boxed, lots of peripherals, 30-40-ish games, oodles more if you include dodgieness
Two original run Playstations, one PS1 with LCD screen. And around 100 games
A flat PS2 with mare games than I care to count.
An Xbox with around 20 games.
Two GameCubes with 10+ games.
A Palm Pilot Z22
An original second run IPod (the big chunky one with the weal), also a first run IPod video
Two DS around 30 games, again much more with extra added dodgieness...
A xbox 360 (we have lots of games but none are mine)
A PS3, probable around 30+ games (disk and digital combined)
As far as computers go 3 old laptops, two e-pcs (one really early, one a bit later), four old PCs, a Blackberry Playbook, android tablet, Big and Smaller IPad, iMac, Mac Performa 620 PowerPC, Macintosh classic II, Sun Spark Station 10 -most with various external disk drives- tape drives - CDROM drives etc, and various CRT monitors/TVs.
There are probably more that can't place just now.
As I said, more a hoard than a collection
I'm looking to get an 8bit Atari and disk drive again (I had an 800XL) so if anybody has one they want to swap for any combination of the above, let me know