Probably none? Nearly none?
So far as I know, Electrum uses its own system of seed phrases which it’s developers consider to be better than the BIP39 system used by many other wallets.
I believe Electrum has some compatibility features that must be specifically enabled. Most users probably don’t do that unless they anticipate the need.
The developers of Sparrow Wallet commented
Although it would be relatively simple to implement (as you note, Sparrow already supports the Electrum seed format internally), I’ve held off on doing so because:
- it might be confusing to have two types of seed lists to choose from
- I’m not sure it’s a good idea to keep supporting such an isolated ‘standard’
BlueWallet might have support for Electrum seed phrases.
