That’s exactly what I am working on.
So far I was able to verify the following functionality at the same time, using an unprovisioned (aka. without Fidesmo, but should be the same for the release version) P71 200K chip. The Fidesmo dev card is able to carry these applets as well, but does not have enough storage for all of them at the same time.
- vk-ykhmac (works with keepassxc using the PCSC driver I contributed on dektop and ykdroid on phone if you emulate the Yubico AID): GitHub - DangerousThings/flexsecure-ykhmac: Javacard applet emulating the Yubikey challenge-response interface
- Flex-OTP (loaded with 21 seperate entries; modified my me to impersonate an OG yubikey to work with the yubikey apps): https://github.com/StarGate01/Flex-OTP
- SmartPGP (works with open Keychain, also gnupg and kleopatra): GitHub - github-af/SmartPGP: SmartPGP is a JavaCard implementation of the OpenPGP card specifications
- openjavacard-ndef (works, tested with 2048 bytes r/w storage): GitHub - OpenJavaCard/openjavacard-ndef: NDEF tag implementation for JavaCard
Unfortunately custom AID enumlation is not possible using the Fidesmo ecosystem (at least not easily), so I use the unprovisoned chips and deploy using the Global Platform tools.
In conclusion, I was able to emulate all the functionality I require from my Yubikey.