I suspect we all spend a lot of time researching and selecting tools to do various tasks. I also suspect in many cases we would prefer just to choose one that we know to work that’s recommended by someone with similar requirements. So here´s a list of my suppliers of choice, and hoping that others add theirs.
Firebase enhanced GUI
Firefoo. Saves so much time manipulating data. Easy import / export etc.
EUK Host, based in the UK. I have used them for 20 years including for hosting mission critical business apps for a small Telecoms company.
Sendy combined with AWS. Be careful not to send bad lists but there are ways to clean lists.
Zapier. There are alternatives, but the range of off the shelf solutions is vast. Using it for converting email alerts into Firebase records for automated provisioning for my app.
Mac in the Cloud
If you don´t have a MAC and want an iOS app then https://virtualmacosx.com/ is doing the job for me. Best priced business grade option I found.
People per hour, though also very happy to recommend the guy who did my graphics on app.adventure-hunt.com
GIMP. This one is a bit love / hate. It takes ages to get used to the interface but it really does seem to be able to do anything - and its free. Especially good at adding transparency.