One of the top of the line remote thermometers is the Thermoworks Smoke. They have an upgrade to that as well. They also go on sale fairly often but regular price is about $100. They were as low as $59, I think a few weeks ago. I have one and it is a great 2 probe unit.
Specializing in cool, unique and professional temperature tools. Super-Fast thermocouples, thermistors, infrared thermometers, data logging and more.
www.thermoworks.com
Themopro has a 4 probe unit (TP829). I sprung for one as I like their instant read therms and I liked the 4 probe idea. I used it one time so far. It took some time to learn to use and is a little more complicated than I like, but worked great. I am sure it will be a lot easier to use after I use it a few more times. I think it was $45.
Super Long Range Wireless Meat Thermometer with 4 Probes 【Best in class 1000 feet range】: Equipped with the strongest and most reliable in RF technology, grill thermometer extends range further than ever before. With 1000FT of freedom to take care of other tasks while your digital food...
buythermopro.com
Maverick makes a unit similar to the Theroworks Smoke too. And another option that is popular on this forum is the Meater which has wireless probes which makes it convenient and able to be used on a rotisserie unlike all the wired probe offerings.