Solution

Every index card describes either one module, or two modules with an operation. The title hints at Forget Us Not (commonly abbreviated as F.U.N.). Take each module's 3 digit code, and if there is an operation, perform it.

Clue(s): Module(s): Number:
Baseball position + obfuscated jacket decorations Third Base + Complicated Buttons 229
Ritchey C260 84D Superlogic 112
Kevin from battle royale game The Cube 821
Arrays of pixels - First game in Sega franchise Bitmaps - Sonic the Hedgehog 105
Preservation Maintenance 521
Dodie Smith novel + advanced cables 101 Dalmatians + Complicated Wires 103
Despicable Me villians - Ratchet blocks Vectors - Lombax Cubes 112
That light toggler + a joke in a manual The Switch + Flavor Text 551
Boolean devices Logic Gates 111
Piping system + line segment virtues Plumbing + Chord Qualities 444
Medical radiation - visually impaired set of corridors X-Ray - Blind Maze 214

To extract, organize the numbers so that there are 3 digits in each row, in order. Then read down the left column, down the middle, and then down the right one. This is clued at by the arrangement of the cards. Doing so gives us a message in A1Z26, without the spaces. The numbers at the bottom show how to divide digits.

2 18 15 11 5 14 2 21 20 20 15 14 19 2 15 13 2 1 14 4

This spells out BROKEN BUTTONS BOMB AND, the answer to which is:

BOOM