Gab bans

Payment bans:
Stripe
Paypal
Square
Bitpay
Coinbase

Hosting bans/censorship:
Joyent
Azure
Backblaze
Amazon AWS

Registrar bans/censorship:
asiaregistry
GoDaddy

App Stores:
Apple App Store
Google Play Store
mozilla extension store
Google Chrome extension store

Storefronts:
Shopify

Third-party tools:
embedly
helpscout
pusher
Medium
Mailgun

Crowdfunding websites:
startenginela
patreon

Advertising:
Twitter Ads