I use a Kirk BH-1 on one tripod. That's rated to support 50 lb., weighs 2 lb., cost about $350 but don't appear to be available right now. I also have a Smith-Victor BH8 ballhead on another tripod... rated to support 50 lb., weighs 2 lb., cost $80 when I bought it (but is no longer available). Virtually identical in design, function and capability. The Kirk is better made... all metal. The rubber grips on the S-V head tore and fell off (I replaced with a few wraps of grippy tape that works fine). The S-V's pan movement was very stiff when I first got it, too. I unscrewed the base, cleaned the axle grease out of the ball bearings there, replaced it with a heavy oil (bicycle chain oil) and it's smooth as silk now.
My point is that price isn't always a good indicator... but higher prices usually equate to more reliably good quality. Still, it's "just" a ballhead!
You didn't indicate your largest lens and maximum weight... or the quality of the tripod you'll use the head upon... but for part of my recommendations I'm going to assume you have some long telephotos with tripod mounting collars like the Nikon 200-500mm or Tamron/Sigma 150-600mm.
First, I recommend you get a ballhead with an Arca-Swiss compatible quick release platform (more on why this is recommended below). This is by far the most widely used quick release system. Many manufacturers make products compatible with it. You will need a matching mounting plate for your camera and one for each lens with a tripod collar (unless they are a Tamron or Sigma, some of which have a built-in dovetail to fit the A-S QR system). A ballhead may come with a "universal" plate, but those are often questionable. One that is specifically fitted to your camera is much better, to prevent accidental twisting and loosening.
Next I recommend a ballhead with between 30 lb. and 55 lb. load capacity. The larger gear you'll put on it, the heavier duty head you should get. Be sure, too, that the ballhead you get has a separate panning access lock (some use a single lock for all movements).
You can use the above directly and immediately. But you also have option of adding a "gimbal adapter" to it if you wish, to better handle really large lenses like those 200-500 and 150-600s. The Wimberley Sidekick (which I use) and the Induro GHBA are examples of gimbaL adapters. These fit into the ballhead, which stays on the tripod, and provide easier work with bigger, heavier lenses.
There are "full size" gimbals, which completely replace any other head on your tripod. Those are great for big, heavy telephotos with tripod collars, too. BUT, that's all they are good for. To use the tripod for anything else you have to swap out the full size gimbal for a different head... be it a ballhead or pan/tilt or whatever. Basically a full size gimbal makes your tripod "big telephotos only", unless you carry around a 2nd head and any tools you might need to swap out the heads.
Until recently I said, "no thanks" to that. I've been using a Wimberley Sidekick for 20+ years with lenses up to 8 and 10 lb. Works great! (I now have a third tripod set up with a full size gimbal, making it pretty specialized. Sees much less use than my tripods with ballheads and the gimbal adapter.)
To use a gimbal adapter requires a ballhead that's reasonably heavy duty (minimum of 30 or 33 lb. capacity... 45 to 55 lb. would be even better). The ballhead also MUST have an Arca-Swiss quick release platform AND must have a separate panning axis lock (the way the adapters work is they fit into the platform and provide the up/down tilt movement, while the ballhead is locked except for it's panning axis which provides the horizontal movement). This is why I recommended what I did above.
Below is a link to B&H Photo, because they carry practically everything and their search features are useful (you can buy wherever you like, of course). First is a list of ballheads. And below that is a list of the gimbals they carry (both full size and adapters).
BALLHEADS:
https://www.bhphotovideo.com/c/products/Tripod-Heads/ci/140/N/4075788769?sort=PRICE_HIGH_TO_LOW&filters=fct_head-type_1544%3Aball-heads%2Cfct_quick-release-system_7375%3Aarca%2Cfct_support-weight_1470%3A30-lb%7C33-lb%7C35-lb%7C40-lb%7C44-lb%7C50-lb%7C55-lbGIMBALS:
https://www.bhphotovideo.com/c/products/Tripod-Heads/ci/140/N/4075788769?sort=PRICE_LOW_TO_HIGH&filters=fct_head-type_1544%3Agimbal-headsEDIT: Someone mentions a 70-200mm lens above. I looked but am not sure what your "big heavy" lens is. If 70-200mm is your largest I DO NOT recommend a gimbal. It's actually too small a lens for use on a gimbal. A gimbal works best when the camera/lens combo can be slid back and forth a little until they are near perfect equilibrium. Then the whole thing will move smoothly with a light touch, to follow moving subjects such as sports and wildlife. The smallest lens I use on a gimbal with is my 100-400mm (about 3.5 lb.)... largest is an 8 lb. 500mm f/4 (I have a vintage 800mm that's even heavier, about 15 lb., but almost never shoot with it... It's more of a collectible than a "shooter").