In rough order of when I think they could be done.
- FCMP++ integration
- Carrot address protocol integration
- Carrot key hierarchy wallets
- Better multisig integration
- P2P encryption and dummy packets
- Better DNS handling when using a VPN
- ASN diversification for peer selection
- Ledger fixing their stupid fucking integrated address display bug
- Constant-time Polyseed decoding
- Multisig wallets with published view-balance secrets for CCS and General Fund
- Wallet-side fee calculation
- Wallet-side PoW verification / chain switching
- DOM-less deserialization for P2P/RPC messages
- RandomX V2 intermediate/light PoW verification
- Recipient address IDs (RIDs)
- Jamtis-RCT light wallets
- Off-chain quantum forward secret addressing protocols
- Header-only sync
- Slim alt-chain PoW pre-verification
- Dummy FCMP++ inputs for input count uniformity
- Transaction format changes for size reduction
- GPU accelerated wallet scanning
- GPU accelerated consensus verification
- Improve blockchain handling concurrency
- Blockchain database migration for size reduction
- Change in
wallet2
format to seperate refresh cache files from user-provided data - User-friendly time-lock puzzles
- Standardized NFC transfer protocols
- 1-of-2 liveness in-person PoS systems
- Mesh networks / satellite services
- More efficient, but still trusless, transaction propogation than pure flooding
- Physical Monero notes
- Advanced payment channels / L2
- On-chain post-quantum key exchange mechanisms
- Post-quantum zero-knowledge proving systems for consensus verification
- Fleshed out post-quantum migration policy
- 10-block-lock workarounds?
- Private smart contracts?
- Client-side-validation to increase L1 throughput?