This incomplete wiki refers to Peninsular Malaysia, as I haven't travelled much to East Malaysia.
Malaysia has numerous mountain ranges running from north to south, but of interest to climbers, are the limestone mogotes, of which several notable ones can be found in relatively populous and accessible cities.
Incomplete list - work in progress;
Batu Caves is a mogote with multiple cliff faces with a large variety of routes. Several areas are more developed than others.
Gua Damai Extreme Park is a well-developed wall of Batu Caves, with generous parking lots, and permanent structures housing an operating company which oversees the equipment and activities for the wall.
Equipment is provided; routes are well-documented, top rope/via ferrata equipment are pre-installed and maintained.
The park management does not check for formal certifications, but you will need the knowledge of:
Setup
Nyamuk Wall is a cliff with 7A+ routes. It is completely uncommercialized - access to Nyamuk Wall is from the backlot between 2 houses, at the end of Lorong Melati.
I was able to park my van in the homes' parking lot for a short while to explore the wall, but only after a short conversation with the homeowners; if parking for longer, the main road, Jalan TIB 3, has plenty of automotive stores and street parking, with Nyamuk Wall being just a short 5 minute walk in.
The short trek up to the wall is relatively precarious, with some relatively steep undergrowth to navigate (that I would not try after wet weather), as well as large boulders on the ground to climb between, before arriving at the base of the wall.
Once at the base of the wall, there's plenty of large, flat rocks to leave your belongings on.
Gua Lepak is a semi-commercialized climbing site maintained by the community with permission from the property's owners, and guides maintaining a Facebook page for Gua Lepak climbing.