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.

Backloggd export: what works today

A CSV export tool is on Backloggd's public roadmap but has not shipped, so nothing can read a Backloggd library directly yet. This page gets a proper importer once it does. Here is what works in the meantime.
Backloggd has no export feature yet, so there is nothing for us to read.
Until they ship one, bring your titles over with the list importer.

Bringing your games over today

  1. Copy the games off your Backloggd pages. It can be as messy as it comes.
  2. Open the list importer. Its cleanup prompt turns a messy paste into one title per line.
  3. Paste the result. Every match is added to your library, and anything unmatched is listed so you can fix it.

Questions

Does Backloggd have an export?
Not yet. Its public roadmap lists a CSV export tool as planned.
Do my ratings come over?
No. A pasted list carries titles only, so each game arrives unrated. Rate 8 of them and GamesGraph starts predicting a score for everything else in your backlog. How the predictions work.
Is there a faster way?
If the same library also lives somewhere else, yes: Steam, GOG, Epic Games, Playnite, HowLongToBeat and Grouvee import directly.