Should be able to get some nice boutique pedals for RM500 per pedal...
The Monte Allum mods for MT2 are great, and should be able to get a used Keeley MT2 for that price too, these hot rodded MT2s make the stock one look like a toy. A new Keeley MT2 is around RM650 though, highly recommended.
Check them out: www.robertkeeley.com

A delay is almost a must, depending on what floats your boat, look around for the DD6 (digital delay) or an AD9 (analogue delay), these should be under RM500. Read up and listen to as much clips as possible on the difference between analogue and digital delays, it will help you alot on your decision.

Modulation, depends whether you would like one in your sound. More common ones that comes to mind are chorus, phaser, and flanger. It really depends on which one you prefer. But I find that chorus is the most useful one, the EHX Small Clone has good reviews, lush sounding chorus and works great with both distortion and clean, give it a shot.

I think you would be able to afford a new Keeley MT2, as both of the other pedals that I mentioned are below RM500.