Plain Bob is the natural extension of Minor, with the extra piece of work being, like Doubles, making 4 blows behind. As before, after making seconds, you do all the down dodges first, dodging two places further out each time (3-4 down, 5-6 down). You then make 4 blows behind (long 7ths), before doing the up dodges, two places earlier each time (5-6 up, 3-4 up), then making seconds.
Like St Simons Doubles and St Clements Minor, in St Simons Triples two bells dodge on the front for the whole of each lead - this is a 4-pull dodge; either count carefully, or just watch for the treble to come back down. The other bells make 3rds between each piece of work, with the dodges coming in the reverse order from Plain Bob. And, like Plain Bob, the extra piece of work is 4 blows behind.
Grandsire extends in a similar way to Plain Bob - compared with Grandsire Doubles, you get extra dodges at the back - 6-7 down, then 6-7 up. So the order of the work is now 3rds, 4-5 down, 6-7 down, 6-7 up, 4-5 up. As in Grandsire Doubles, there is also a hunt bell, who will come out of the hunt by double-dodging 4-5 down at a Bob or Single. The rules for Bobs and Singles are much the same as in Doubles: If you're near the front at a Bob, make 3rds and back in (either unaffected, or then going into the hunt); all the other bells double-dodge immediately, then carry on with the work that would normally follow a single dodge in that position. e.g. if you are about to dodge 6-7 up, a Bob would be called when you are in 4ths place, so you double-dodge 4-5 up, then do 3rds next time.
There are also other double-hunt methods, like Grandsire, for instance St Clements Triples, which is like St Clements Minor, with all the work shifted one place towards the back (e.g. instead of making 2nds, make 3rds; instead of 5-6 down, dodge 6-7 down). The calls are the same as Grandsire.
Now two principles (that is, every bell does the same work, there is no hunt bell); Stedman and Erin. Both extend the double dodging in 4-5 up and 4-5 down in Doubles by adding double-dodges in 6-7 up and 6-7 down. The frontwork in each is unchanged. Note that the starts are different in Erin from those in Stedman. The calls in Stedman Triples are now made at the end of a "six", rather than in the middle, as in Doubles; the bells at the back stay there for another six, while the bell dodging 4-5 up makes 5ths and dodges 4-5 down (as in a plain course of Doubles).
Another principle is Titanic. For more information, see here.
And now a new principle, named after Andrew Tibbetts; AJWT Cyclic Triples, which has rotational symmetry, but not reflective, so be careful which way the double dodges go.
This, and other odds and ends, suitable for a bit of fun, or for training, are here. A small selection of Doubles and Triples methods is also here.