You can add (and execute) bookmarklets entirely in Android Chrome.
The caveat: it takes more work than just drag-and-drop in the desktop counterpart.
Save a bookmarklet (Android Chrome)
Long tap the desired bookmarklet
Select Copy link address
Go to Menu (three dots) and tap the Star (bookmark)
BEFORE IT DISAPPEARS, tap EDIT! (at the bottom)
Works in Chrome mobile. Here's the recipe:
Create a bookmarklet = add a script to your bookmarks:
on Chrome PC¹, then sync (so your bookmarks show up in Chrome mobile on your phone)
or directly in Chrome mobile on your phone²
Do not invoke/call the script (on phone) by looking it up in Chrome Bookmarks (menu [ ⋮ ] / Bookmarks) → that doesn't ...
If I understand your question correctly, you want to: