Here we go again by popular demand, a third and final attempt.
Any training (whether it's called "advanced", refresher" or "continuation") is a good thing and will lead to improved confidence, safety and (most of all) FUN

. In terms of bang for the buck it's a lot better than going for a £100 hamburger but, unfortunately, most PPLs don't do enough of it.
If you can find somewhere with appropriate aircraft and instructors you could probably mx'n'match from a list like this:
- stall recoveries (approach, departure, accelerated, various attitudes)
- unusual attitude recoveries (nose very high/low and inverted)
- Slow flight, accurate steep turns and MRTs
- spin recoveries ("academic", from manouevre, precision and high rotational)
- spiral dive recoveries
- aerobatics (as relaxed or as strict as you want them to be)
- PFLs using constant aspect technique
- "point and power" approach techniques and precision landings
- dealing with systems failures
- improved VisNav techniques (Max drift, DI visualisation, SCA)
- improved RadNav techniques (DI visualisation for holds, point-point IF)
- complex or tailwheel conversions - or just trying a new type
... but not all schools/clubs have experience of offering some of these items, have instructors with the necessary skills or have suitable aircraft available.
One final thought. Everyone is starting from a unique point and wants to put a unique amount of time and money into the process of reaching a unique point; I would therefore recommend agreeing a bespoke plan with the instructor rather than opting for a fixed course.
HFD