Mulligans
Aggressive dragon paladin with secrets. Either a secret opener or dragon opener can result in fast starts.
Desperate Measure, Firetree Witchdoctor and Bronze Herald help to act as pseudo card draw by replacing themselves.
The 2/1 from Marsh Drake can be dealt with in a number of ways, either with the Mysterious Blade, the divine Shield from Cathedral Gargoyle or even just leaving it up as a way to trigger secrets.
Only the secrets that work with Rhyssa are hard run, plus Desperate Measure for some additional uncertainty to the opponent and potential duplicates of the best secrets that work with her.