Since IPFS stores all the data of the frontend of a site, static web pages are particularly well-suited to be deployed to IPFS. Static site frameworks such as Gatsby, Next.js, Hugo, Jekyll, etc. can be used effectively.
The JAMstack is also an effective stack for an IPFS website. Frontends can be written by any framework such as React, Vue, Angular, etc.
Application with backends can also work with IPFS, provided a few caveats. First of all, the backend itself cannot be hosted on IPFS, only the frontend. The management of the server, therefore, is not in the hands of Fleek.
Additionally, Fleek supports the use of env variables and docker images.