The most common pickup swap so far, has been Fender Am Std, followed by Nordstrand. There's a Neo pickup made by a small maker (James Reid?), and I think one person mentioned a Bartolini.
The biggest deal pickup-wise, is to do whatever it takes to get proper pickup height and alignment to Fender specs. I've looked at a half-dozen, and so far every single one had the pickup halves set too flat out of the box, and not at the proper height. On two of the four I've set up so far, I had to pull the outer bass-side screw, and re-insert it at a steeper angle in order to get the proper break angle between the pickup halves. If you (or your setup tech) take care of this important detail, the stock pickup will give you excellent balance string-to-string, and possibly save you the cost of an aftermarket pickup.
Bridge-wise, it's important to stick with 18mm spacing, as there's not enough fingerboard width for anything wider. You'll have to use the Advanced Search for "bridge" within this thread, but we've got quite a bit of stuff between us. Hipshot vintage top-load,Type A, eBay specials, etc.
So far, nothing that's a straight drop-in as far as screw holes go.
TBH, unless you have a heavy attack and need a rail-type or lockdown bridge or want the slight change in sustain envelope that you get from high-mass bridges, there's no pressing reason to change out the stock one. The VM P5 already has the appropriate amount of sustain if you're going for the vintage P-bass vibe.
On the early VM basses, you could get a small improvement in tone by swapping out the cast pot-metal saddles for machined steel or alloy. However on this one, there's casting line on the stock saddles, just the swirl pattern on the ends from being machined out of solid rod. I tried fitting threaded vintage steel saddles to alternate strings, and didn't hear the expected difference from string to string.
Some have slight spacing problems if you look at the way the strings pass over the pickup poles, but tweaking the neck joint to one side or the other, or at most, crazy-gluing a few aluminum soda-can shims to the ends of the inner saddles, will take care of that.