We've been quite successful in eliminating these lately (#7905, #7691).

It would be nice to disentangle the wallet and non-wallet initialization completely so that init.cpp no longer depends on the wallet (and thus, libbitcoin_server.a no longer depends on libbitcoin_wallet.a - the other way is fine, a circular dependency is not).

Ignoring the GUI for now (which still needs some work in this direction), the following are left:

• init.cpp: these are mostly self-contained and short. ([wallet] Remove Wallet dependencies from init.cpp #10762)
  • print BerkeleyDB version should probably be moved to CWallet::InitLoadWallet CWallet::Verify (fixed in init: Move berkeleydb version reporting to wallet #8036).
  • wallet-specfic option interaction (-walletbroadcast, -prune+-rescan) should move to wallet module (possibly a new call that can be called in addition to InitParameterInteraction())
  • printing setKeyPool size etc should probably be moved to CWallet::InitLoadWallet.
  • wallet initialization/verify/shutdown - maybe this could be replaced by a general registration system for initialization/interrupt/shutdown functions, called as signals in the appropriate places. The same could be used by other modules
  • -disablewallet could result in the wallet not being registered at all, and that can all be handled from outside init.
• RPC still has some calls that vary depending on wallet support. We should split these up. This is the more annoying part as it will involve API changes. No non-wallet RPC call should make an assumption about "a wallet".
  • rpcmisc.cpp
    • getinfo - this call is already on the list to be deprecated for a long time ((finally) remove getinfo #10838)
    • validateaddress - should be split up into an utility-only validateaddress and a wallet-specific call getaddressinfo (name open for discussion) ([RPC] Split part of validateaddress into getaddressinfo #10583)
    • createmultisig - same. createmultisig and walletcreatemultisig or so ([RPC] Disallow using addresses in createmultisig #11415)
  • rpcblockchain.cpp
    • signrawtransaction - should be split into an utility-only signrawtransaction and a wallet-specific call walletsignrawtransaction ([RPC] Split signrawtransaction into wallet and non-wallet RPC command #10579)
  • remove deprecated validateaddress and signrawtransaction wallet dependency completely ([Wallet] [RPC] Remove deprecated wallet rpc features from bitcoin_server #12490)
• Mining: no ENABLE_WALLET but an implicit assumption and a circuitous registration system. The generate call should be a wallet-specific call, whereas generatetoaddress is core. See discussion in [mining] allow other signal listeners to provide scripts for mining #6481. (done in rpc: Move the generate RPC call to rpcwallet #10683).
• in httprpc.cpp, there are #ifdef ENABLE_WALLETs protecting registration/unregistration of the wallet endpoint. These can trivially be replaced with calls into the WalletInitInterface.
• in interfaces/node.cpp, #ifdef ENABLE_WALLET protects the calls to getWallets(). This can easily be replaced by calls into a wallet manager/dummy wallet manager.

The first phase would be to introduce the new (wallet-only) methods, then a release later remove wallet functionality from the core-only calls.