This is the best free one imho:
https://vborg.vbsupport.ru/showthread.php?t=250202
I've used it countless times and on a few occasions helped others integrate custom scripts on new pages by this mod w/o the same errors presenting themselves that you would encounter when manually creating a page in the suite cms or similar. It's basically a cms and page maker, love it and one of my all-time favorite mods! Check his profile there is a 3.x and 4.x version available.
Edit: Create custom pages and custom templates, use certain templates on specific pages etc its very versatile I can't stress that enough.