RouterGods - This is a Meetup group that I'm a part of and sometimes I run labs as a co-organizer. This group was founded back in 2008 by Humphrey Cheung as a CCIE study group and has since grown to over 1,250 members. It's currently the largest Cisco study group on Meetup.com and definitely one to join. Since we do balance between local and remote meetups, we have a user base that's pretty geographically distributed. It's a great place to network since we're always either bouncing ideas back and forth in our chat or jumping on a nightly Hangout to lab together.
ISE Communities - If you need official ISE help, have a question about ISE, need support, training, and a bunch of other goodies, this is the place to go. I know for a fact that a lot of smart Cisco folks are constantly monitoring this community and will jump in to answer questions. This is the number one place to go for ISE-related stuff on the internet.
Lab Minutes - This site has probably the best collection of digestible small Firepower, ISE, and wireless videos. They are free to stream and are extremely well-priced if you would like to download the videos. What I love about this site is that they are constantly turning out new videos for different versions and make it very easy to follow along. Metha, the one who is in the videos, also takes a lot of time out to respond to user questions in their forums.
Micronics Training - This is a training company owned by the famous Narbik Kocharians who is a walking talking IOS encyclopedia. He's the author of the CCIE v5 CiscoPress Official Certification Guide and he's probably the best bootcamp instructor out there for R&S. There's a great RouterGods review written on his bootcamp which you could read here. My personal experience with the company comes from the fact that I just recently purchased the online "Zero to Hero Security" bootcamp which lasts approximately 16 weeks. I have to say that I've had my expectations completely exceeded by this class. I've also had the honor of being able to sit in Narbik's CCIE R&S bootcamp for a couple days and I was definitely impressed. It's unlike any bootcamp I've ever been to in a very good way.
Narbik Academy - Full disclosure: I haven't purchased a subscription for this site so I can't personally comment on some of the content yet. I wanted to definitely mention it because it's another Micronics site where they're doing more focused Video on Demand series and providing some amazing articles. Piotr Matusiak is the instructor from my Security bootcamp and he seems to be a big contributor to this site so I have full faith and credit that it will be some amazing content.
TwistedIT - Jason Lunde was the Data Center trainer for IPExpert and probably the biggest factor in my passing the CCIE Data Center lab. After IPX closed shop, he's been working on his own training videos for data center. I have to say his videos are probably the easiest videos to understanding ACI concepts so if you're thinking about going towards the CCIE DC v2, I highly recommend checking these out. I know he's also working on some more training videos on the horizon.
XtremeIE - This is a site from another former IPExpert instructor JP Cedreno. I haven't personally watched his videos but I plan on doing so soon since I've heard nothing but great things. I know there are a lot of R&S providers for VODs out there but it's always good to have another great instructor available.
NetworkDojo - The CCIE Wireless track is one of the most neglected tracks when it comes to other training providers. I heard IPExpert used to be the leader for wireless material for the IE but they've closed shop. Thankfully, their former wireless instructor, Jeff Rensink, has opened up his own training company for wireless. If you're interested in updated CCIE Wireless material, definitely check this out.
CollabCert - Another track that hasn't received a lot of love from training providers is the CCIE Collaboration track but I've heard nothing but excellent things about Vik Malhi's company that he opened up. If that's your track, please check it out.
TechExams - I don't have a lot of time to frequent this forum as I used to but it'll always have a special place in my heart. I found this forum when I was very new to IT and amazing friends I met off of here were priceless. When I was just a wee little engineer, I would come here for technical and career advice. I have to say that I learned any amazing amount about how the industry works and avoided a lot of career traps thanks to the people on this forum.