There are many classic styles, so you might check out what the locally available styles do.
The japanese jiu-jitsu style in which i train focuses on standup grappling and controlling or pinning an opponent afterwards on the ground.
We do almost no takedowns but a lot of stand-up locks and throws. Because of that our ground-training is mostly with us on top in a better position.
So if you realy want to grapple and be good on the ground, i suppose you better go for BJJ.
Please note, that my traininggroup is located in an police-facility and therefore probably focuses more on pinning/handcuffing somebody than other styles.
Another difference between japanese and brasilian jiujitsu is that strikes are incorparated in the japanese style. But as a boxer i also have to say, that only teachers with an additional striking background (have seen many masters, with black belts in karate) do incorparate decent strikes. The thing with the striking is, that there are are many jiujitsu people, who can't strike well and you may have to train with them. So take the additional striking with a grain of salt and lookup your local people.
As in most cases, the people and teachers matter more than style.