If you want high level campaigns that begin play at levels 10-20, then there is very little available. Tales from the Yawning Portal has several Tier 3 and Tier 4 adventures. I am aware of The Complete Roslof Keep which is geared towards Tier 4 players (available on DriveThru RPG), Escape from Skullcano Island which is designed for Tier 4, and Crypt of the Devil Lich which is for Level 15+ (available from Goodman Games, they just Kickstarted a new edition so that might be available soon). In addition to the link Keith shared above, the DM's Guild allows sorting by adventure tier, so you could potentially find some good one shots or short adventure arcs that way. There are several long campaigns that range from Tier 1 to Tier 4 that I've listed below. The following official WotC campaigns all go to level 10+: Lost Mine of Phandelver combined with Essentials Kit - Level 1-12 Tyranny of Dragons (Hoard of the Dragon Queen + The Rise of Tiamat) - Level 1-15 (Extend it to Level 16 with Palace of the Red Pasha on DM's Guild) Princes of the Apocalypse - Level 1-15 Out of the Abyss - Level 1-15 Curse of Strahd - Level 1-10+ Storm King's Thunder - Level 1-11+ Tomb of Annihilation - Level 1-11+ Dungeon of the Mad Mage - Level 5-20 Ghosts of Saltmarsh - Level 1-12 Baldur's Gate: descent into Avernus - Level 1-13 Icewind Dale: Rime of the Frostmaiden - Level 1-12 Candlekeep Mysteries - Level 1 - 16 Some non-WotC campaigns to check out: Scarlet Citadel - Level 1-10 Empire of the Ghouls - Level 1-13 Tales of the Old Margreve - Level 1-10 Aegis of Empires - Level 1-17 (currently being released episodically, the first two of six episodes are on the marketplace so far - The Book in the Old House and The Ebon Soul ) Zeitgeist - Level 3-20 War of the Burning Sky - Level 3-19+ Odyssey of the Dragonlords - Level 1-15, plus epic quests that can take players to Level 20 Not on the Marketplace, will have to build yourself on Roll20: Call from the Deep - Level 1-12 (available on DM's Guild) Lost City of Mezro - Level 1-16 - (combines nicely with Tomb of Annihilation to extend that campaign, available on DM's Guild) The Crystal Corruption - Level 1-10+ (Kickstarter, available soon) The Demonplague - Level 1-20 (available through DriveThru RPG) Dragon Relics - Level 1-12 (available on DM's Guild) Freyja's Tears - Level 1-20 (Kickstarter, available soon) Hand of the Eight - Level 1-20 (available from DM Dave) Heckna - Level 1-10 (Kickstarter, available soon) Journey to Ragnarok - Level 1-15 (available through DriveThru RPG) Rappan Athuk (5e) - Level 1-20 (available through DriveThru RPG) Lost Tales of Myth Drannor (Adventurer's League Series, available on DM's Guild) - Tier 1 - Tier 4 Knights of the Shadow Realm - Level 1-20 (available through DriveThru RPG) The Red Opera - Single Tier Campaign that is designed to scale to any Tier of your choice to play in - 5 total levels of play (7 if you start at Tier 1). (available from Apotheosis Studos) Sirens - Level 1-20 (Kickstarter, available soon) Rise of the Drow - Level 1-20 (available from AAW Games) Sea King's Malice - Level 1-10 (available from Frog God Games) Dawn of the Necromancer - Level 1-20 (Kickstarter, available soon) Carbon Overdrive (Carbon 2185 Adventure) - Level 1-10 (Kickstarter, available soon) The Complete White Ship Campaign - Level 1-12