Some stuff I forgot to put in the main video/ learned since then (I added it to the comments and the description of the video). If you have some more useful improvements/knowledge/experience/ relevant footage please write in the comments and I'll add it. Later, I'll put everything in a part 2 video.
A MUST!!!! From a realistic Knife competition: A basic throw to ground and pound finish while trapping the knife holding arm.
1:35 A must!!! A great tip. During Arm bar, cross your legs on the opponent's free second arm (just in case, if he has another weapon).
A must!!! during the arm bar, the opponent may manage to bite you. be ready for that. handle the pain and Destroy his arm. It's might be possible for you to straighten the leg above his head and hit his head against the floor like is shown here as an example for biting defense.
A must!!! 0:36 A great scramble to see- when the opponent stands up during an arm bar. 1:10 in the same video above- A take down while holding one side of the opponent to a flying arm bar. it's dangerous on concrete (it's less dangerous if the opponent is lower, then a jump is not involved), but it's good to know that you can get an arm bar from this direction as well (and not just with a step over the arm).
A must!! 2:45 a knee on the forearm on the ground to a knife strip. 2:53 in the same video above: another version for an arm bar from the back against a knife.
While executing the Russian tie, the arm which is under the opponent's shoulder (The shoulder of the knife holding hand) can reach under the shoulder to deal with the opponent's free hand if he tries to break our Russian tie with it, As shown here at 10:35
https://www.youtube.com/watch?v=WJanEpccxxQ
In addition, circling towards the knife holding arm, as I did at the realistic demonstrations in the knife defense video, helps to prevent an escape from the Russian tie.
Plus you can see at the link above at 11:35 (and throughout the video at the link above) how the Russian Tie can be used to get the back.
https://www.youtube.com/watch?v=ExddR0Vv8f0
23:37 a wrist lock and knife strip with the opposite armpit. I showed a regular one at 13:35 in the knife defense video.
A great tip for a stronger kimura from the back:
https://www.youtube.com/watch?v=faA0-1Lde9A&list=LL&index=38
https://www.youtube.com/watch?v=1zDiHWeceew
3:25 another great example of kimura sumi gaeshi from standing to arm bar
Ishida vs. Wilcox
https://www.youtube.com/watch?v=K3iqKfzleeY&list=LL&index=62
1:34 An interesting forearm submission from Kesa Gatame/ Scarf Hold/ Headlock.
https://www.youtube.com/watch?v=a_zDIC8tmhI
Omoplata with a wrist lock
https://www.youtube.com/watch?v=4RfijSXgIXQ
An amazing analysis. A Russian tie uchimata to a back take in freestyle wrestling.