Here is a list of places to submit your podcast RSS feed to:-

Apple Podcasts   read the Apple submission guidance here.

Google Podcasts – learn how to get listed.

Youtube – convert your podcast into a video and get access to everything youtube has to offer.

Audible – Part of the Amazon family of sites.

Podomatic – a strong directory with some great features such as rankings within a niche.

Listennotes – a nice directory.

Player FM – another good brand.