Anyone ever done overhead squats with dumbells.
That would be so awkward but challenging.
I've seen it attempted. I haven't seen it done in any way that would warrant me calling it good or worth it.
I won't directly answer the question in the OP, if for no other reason than that there is no single best routine based solely on the equipment available. But, here be some thoughts of mine on what to do with just DBs and an adjustable bench.
Dumbbells are pretty easy to figure out for the upper body: do some form of DB bench press, some form of DB overhead press, and some form of DB row (upright rows included) for equivalent volume to the pressing. If isolations are going to be involved, then either some form of fly or pullover for the chest, frontal raises for anterior delts, lateral raises for middle delts, rear delt flys for rear delts, lying straight-arm extensions for lats, some form of elbow extension for tris and elbow flexion for bis, and possibly wrist curls and wrist extensions. Of course, use what you need in a minimalistic manner (if your weak points will be solved by a single compound or by 3 iso's, the compund is probably the better choice) and keep things balanced.
For lower body, DBs can be a little more problematic, because even when you find a good movement, it may be hard to utilise enough weight for it to be worth it, especially past the beginner stage. There are several DB squat variations, including Goblet squats, Bulgarian split squats, placing the DBs together on the floor and tackling them like a deadlift (but with squatting mechanics rather than pulling mechanics), and so forth. The ones I've just listed would be my preferences, but that's not to say other DB squat variations wouldn't work also. Lunges and step ups would be good, too, depending on the individual. For glutes and hamstrings, you could do DB deadlifts, SLDLs, RDLs, 1-legged DLs. Depending on the bench being used and your weight, you might also be able to do hyperextensions off the back of the bench, although for most people on most benches, this could prove to be failtastic. Reverse hyperextensions off the bench would probabky be more feasible, as would lying leg curls and seated leg extensions holding a DB between your feet. For anterior calves, sit on the bench with your heels on the edge of the bench and DB between your feet, and do some dorsi flexion with the weight. For posterior calves, it'll be a bit harder with DBs. You can still do standing calf raises holding the DBs at your sides, but the weight may be insufficient. You can do seated calf raises with the DBs on the base of your quads - same position you'd put them before lying back for a DBBP or kicking them up for shoulder presses.
