Patreon

Patreon predates the current wave of newsletter platforms and is built around ongoing membership rather than single-issue paywalls — readers pledge a monthly amount in exchange for perks like early access, bonus content, or a community space, rather than paying specifically to unlock your email.

It's a reasonable fit if your newsletter is one piece of a bigger creative output, say alongside a podcast or video content, since Patreon is used across mediums and your existing audience there may already be used to supporting creators through it, rather than switching to a newsletter-specific paywall.