Generic backend server

What would be good generic backend services to run, for making (web)apps?

Based on functionality/need, maturity, standardization, and ease of maintenance, this would be my plan for a generic backend-server:

Service Protocol Implementations
pubsub STOMP RabbitMQ, ActiveMQ, …
database CouchDB CouchDB, pouchdb-server, CouchBase
filesystem WebDAV ownCloud, seafile, …
reverse https/cors proxy HTTPS Caddy, nginx, apache, …
cron’ed webapps HTML5 electron, nwjs, …
(email) SMTP haraka + export to couchdb, …
(instant messaging) matrix synapse, ..
(dev environment) https+git gitlab, ..
(distributed filesystem) IPFS go-ipfs, js-ipfs
(search)   elastic-search