If you're looking for market/competition research, I'd recommend https://coscout.com as well, for info about companies, funding, competitors, tech stack etc
It's in alpha right now, so you'll have to get in the waitlist, though they're only a few weeks away from launching AFAIK.
Full disclosure: A friend of mine is building this :)
> mails,
https://founderkit.com/growth-marketing/email-marketing/revi...
https://stackshare.io/email-marketing
https://zapier.com/learn/email-marketing/
> text gateways,
https://founderkit.com/apis/sms/reviews
https://stackshare.io/voice-and-sms
> payments
https://founderkit.com/apis/credit-card-processing/reviews
https://stackshare.io/payment-services
Both have categories:
https://stackshare.io/categories
https://founderkit.com/reviews