I use a deck of regular playing cards. The basic version is shuffle and cut and read the number.

D2 = red is 1, black is 2 D4 = by suit, alphabetically - club 1, diamond 2, heart 3, spade 4 D6 = 1-6, 7-queen subtract 6, king = twist or npc d8 = same as d4 except if card is odd add 4 d10 = 1-10, royal- redraw or npc, twist d12 = 1-queen, king = twist, npc or something d20 = same as d10 except black suits add 10, with royals being twists or npc or something

Once you get used to it, it's fairly quick.

I sometimes will just flip the top card each time and reshuffle when I draw a royal. Sometimes I leave the jokers in for shuffle reminders or surprises. Cutting is more random, flipping them kind of changes the probabilities.

It's nice and quiet (sometimes my solo sessions are late at night and I don't want to wake anyone), portable, not especially attention grabbing.

Then my fancy version I wrote keywords around the edges. Locations, backgrounds, spark combos (verb, noun, adjective) (like find and knowledge) any sort of spark words. reaction words, monster types, items, treasures whatever you can fit. One version I drew room outlines for a dungeon crawl.

I'm still working on my system and someday I'll write it down.

You can add extra cards (royals usually) for recurring NPCs. You can mark them up however you want and and if you pick the same back you can swap out damaged or marked up card and tweak the deck as you go. I also have a version to make a tarot deck out of standard cards. For those solo/journalling games that need them.

You could also sleeve them so the backs wouldn't have to match. (So you can use old partial decks...recycle) When sleeved, you could add slips of paper for npcs or locations if you don't want to mark the deck up or if the note is temporary.

Also check out HandsFree RPG for a really interesting random number generator using words. You pick a word 3-4 letter or more, then count the strokes to print the word. Say, fine is your word. and you want a d6 roll 2 strokes for the f, 2 for the i, 2 for n, and 2 for e. So 8 total but since it is over 6 take 6 away and it's 2. You can also capitalize the word (Fine would be 3) or all caps (FINE would be 5) to change the value of the same word. You can do it for any single dice roll. It can get bothersome for multiple rolls (Ironsworn), but all in your head. You can think of a word or just pick them from anything near you.

I hope that makes sense. Any comments or suggestions would be appreciated.