I am curious which wallets are supporting SEP-0007 - URI Scheme to facilitate delegated signing already or have it on their roadmap for the near future.
Mooney is the first wallet to support uri schemes according to SEP-007.
However, it is only for payments, inflation, trustlines and offers, signing transactions will be available in version 2.0.
(This is one of my projects)
This will take a little time, though, as there's a lot of requirement to get right like multi-signature and accurate description of every kind of operation.
I'll likely generate a few transactions using this in StellarGuard, as multisig setup is the most complicated part of onboarding so far and I'm just sending people to Stellar Labs or copy the XDR themselves.
As far as registering handlers, the story around multisig in that SEP is a bit murky, so I'm not quite sure how I should approach it. I'll likely let people scan QR codes with these URIs to import them, but probably won't register a URI handler. Waiting to see how things shake out.