I started this project a few weeks ago for my transition from Firefox to Falkon, and I've been using it ever since. It's a daemon running on a local port for all web browsers to access. It now provides two features: Top Sites, inspired by Firefox's new tab, and a search bar with customizable engines, inspired by DDG's bangs (but it's a slash instead of a bang, to save you a shift press).
Check out the source code (0BSD): utab
utab is almost definitely not what you exactly wanted, given its intentionally limited config options and features, but given the power of free software anyone can build upon it themselves.
Also, it is 100% JavaScript-free.