I have probably something like 15 controllers for each Xbox (360 and One); the reason is not that I'm crazy tho :) I have 4 kids and they always lose them or put them somewhere or eat chips and THEN use the controllers etc..
so yah for the Xbox One for instance I have 2 elites (mines one for my PC and one in my living room, + 4 there for the kids to play with) and then I have maybe 2 per Xbox One (I have 4 Xbox One in total) downstairs in our play room (where all the Xboxes and TVs are)

I have two DS 4 controllers, 2 DS 3, 2 DS2, 2 360 controllers (one wireless), three NES controllers and three N64 controllers.

2 - 3 controllers per system on average as long as the systems are popular. When the systems become legacy, I often sell one or two controllers since my friends prefer multiplayer on the newer systems.

2 Competition Pro for C64 and Amiga
3 PS1 controllers: 1 digital, 1 analog + 1 DualShock 1
1 GameCube controller... sold the second controller
2 Xbox "Controller S" gamepads
1 Wii Remote+ and 1 Nunchuk (connected to my Wii U)... sold the second set together with the Wii
3 Xbox360 controllers: 2 wired (perfect for PC, SteamLink + Android devices) + 1 wireless... sold the second wireless
2 PS3 controllers: 1 Six-Axis + 1 DS3
2 Move controllers (now used for PSVR) and 1 Move navigation controller
1 Wii U tablet controller... sold the Wii U Pro controller
2 Xbox One controllers: 1 standard + 1 "Ocean Shadow"
4 PS4 controllers: 2 DS4 (can also be used with my Xperia phone) + 2 Vitas (remote play)
1 Aim-Controller for PSVR
1 guitar controller + 1 drum for Rock Band / Guitar Hero...

I also have some older pc controllers for the gameport laying around: the "Gravis PC Gamepad" (SNES-pad shaped) and the "Gravis Gamepad Pro" (PS1-pad shaped) were perfect for any PC game with digital controls; the "Gravis Analog" and "Gravis Analog Pro" were great for games like Wing Commander and racing games.

I had more but either I gave to my brother or they no longer work (for older systems).

2 PS4
1 PS3
2 PS2
1 PS1

2 Switch (1 set of Joycons)
2 WiiU (Pad and Pro)
2 Wii
3 Gamecube
2 N64
1 SNES
1 NES

1 PC (Logitech game pad)

6 PS3 controllers and 3 PS4 controllers plus 1 PS2 controller for a total of 10.

I have 4 GameCube controllers (got one Smash controller for Smash U) , and 4 Wiimotes (one is 3rd party, but got that for free)

I have so many Xbox Ones. So I have so many Xbox One controllers. I think I have about eight.

I currently have 3 XB1 controllers, 1 PS4 controller, and 5 Wii U controllers (3 wiimotes, one Nyko pro-style, and the gamepad).

I have 4 Wiimotes, 2 PS4, Wii U Pro, Switch Pro, 1 set of Joycons.... and an Ouya controller :(

Only have two per console. PS3 and PS4. Black and white each.