FOSDEM PHP&Friends is not limited to just PHP-related talks. There have been sessions covering a wide range of topics supporting PHP developers and DevOps as well, and we encourage you to "think outside the box" to come up with your own unique topics.
It is advisable to submit a few talk ideas, not just one. By submitting a single talk you may reduce your chances of being selected.
To get the ideas flowing, here's a few suggestions: