Maybe consider a kickstarter as well. Qutebrowser apparently does this once a year so the main dev can work on it full time during the summer break from his university. Seems fairly effective.
qutebrowser author here - I think Kickstarter (or similar crowdfunding platforms) work best when you have a given timeframe (like the 1-2 months I have once a year) and a tangible feature to advertise as part of it. For qutebrowser, that was the new QtWebEngine backend last year (https://igg.me/at/qutebrowser) and a completely new config system this year.