A great place to find a boost is with amps that are designed with boosts already as part of them or with a channel that is boosted. It seems designers have already found what boost works well with that amp. Then you can always just turn it off if it's a switch and use your own boost pedal or change the channel from the boosted one. As an example, the EVH5150III red channel sounds very boosted. So it doesn't really need a boost. Then you have amps like Marshall Origin, Some Friedman, PRS, just look at the footswitches and if there is "boost" or sometimes "gain" written on them, you have a proprietary boost with the amp and you should try using that first, IMO. They usually sound very good.