sync with Steam
Import
sync with Epic Games
Import
sync with GOG
Import
import from Playnite
Import
import from IsThereAnyDeal
Import
HLTB
Import
Grouvee
Import
import from text
Import
GG.Deals doesn't offer an export function, and Backloggd has it on their public roadmap. In the meantime, you can try importing a text list.

Import from Text

Use this to import games from services that allow data exports, or any personal spreadsheet or list you might have.
1. Do you already have a clean list?
If it looks like the example below, you can paste it directly in Step 3. 
Hades
Stardew Valley
Disco Elysium
2. Clean up messy data (CSV, JSON, etc.)
Use this ChatGPT prompt to clean your data. Simply paste your text (or attach a file) into the chat, and it will return a clean list of games.
3. Paste the result here
and wait a few seconds
Done? Check your profile and playlist