Внесу свой скромный вклад.
Там не все именно бэк, местами могут быть только фронтенды или описания, прошу (кому не лень) проинспектировать и оставить актуальные ссылки только, кто имеет полный набор или расписать где-что.
Если некому будет, попрошу чуть позже со своей команды ребят провести исследование.

https://github.com/enjin
https://github.com/coinbase
https://github.com/Jaxx-io
https://github.com/DMarketCom
https://github.com/bitcoin-wallet/bitcoin-wallet
https://github.com/citowise
https://github.com/bitpay
https://github.com/gettyio/tronwallet-mobile
https://github.com/tenx-tech
https://github.com/wirexapp
https://github.com/TrustWallet
https://github.com/EdgeApp
https://github.com/mycelium-com
https://github.com/spesmilo
https://github.com/btccom
https://github.com/breadwallet
https://github.com/celsiusnetwork
https://github.com/MidasCore
https://github.com/ToastWallet
https://github.com/Bitcoin-com
https://github.com/cobowallet
https://github.com/xapo
https://github.com/greenaddress
https://github.com/bitpay/copay
https://github.com/bither
https://github.com/freewallet
https://github.com/luno
https://github.com/mobiwallet
https://github.com/eidoo
https://github.com/pumapayio
https://github.com/Internet-of-People/iop-core/releases/tag/v6.2.2
https://github.com/ACINQ/eclair-wallet
https://github.com/NetCents
https://github.com/Samourai-Wallet/
https://github.com/bsimic0001/AegisWallet
https://github.com/bitpiedotcom/bitpie-docs/blob/master/index.rst
https://github.com/airgap-it
https://github.com/bitwala
https://github.com/SpectroCoin
https://github.com/humaniq
https://github.com/EOtrade
https://github.com/emercoin/emercoin/releases