Highlighting some of the options for random tables and generators on DM's Guild
The DM's Guild is the D&D Marketplace for digital content created by the community and also for older versions of D&D.
Disclaimer. I'm an affiliate for DM's Guild and I also create a lot of products with random tables on DM's Guild..
D&D has a long tradition of random encounter tables and this is continued with for 5E on DM's Guild, starting with Hexcrawling - Wilderness Exploration and Random Encounters.
Waterdeep: City of Spendours has encounters with random tables for them by ward
Solo generators and tables deserves its own guide but you can start with the Solo Adventurer's Toolbox. Encounters for wilderness, urban and dungeon, random generation of dungeons, wilderness terrain, merchants and other scenarios for solo D&D. D&D Solo Adventure: Tables Of Doom has random tables to generate monsters, traps, clues, loot and other elements for solo adventures.
If you like doors then the Incredible World of Doors and Locks has many random tables in addition to many ways to make use of that dungeon classic.
Then there are rumours with Strange Tidings
The Deck of Multitudinous Things provides a story-based approach to Deck of Many Things supported by random tables
For characters you can add personality traits according to your character stats with Ability Traits, find some Trinkets with Loot the Room or work out magic items for PCs and NPCs with character magic item tables (one of mine)
More Guild Titles
I'll keep this guide updated so please suggest DM Guild titles in the comments or on twitter to @DuncanThom