Tools which I've found are handy during my DIY days (and still going are):

- 1/2 drive and 3/8 drive socket sets in metric units - good brands such as Kinchrome, sidchrome and possibly even stanley. Don't buy cheap sets.

- Ring spanner sets and general spanners in metric once again.

- A Rubber mallet/hammer is handy sometimes too

- General pliers

All the above really apply to suspension (which i've done by myself) but will most probably apply to other mods.

As for engine rebuilds, thats pretty specialist.