The thing that makes these techniques great is that they work well on larger attackers, keep in mind this is only for self defense not for starting brawls. Also, in order for a person to be able to perfectly perform these techniques, they must practice them under the supervision of a self defense instructor in order to help you master these techniques.
1.) Armbar/Ude-hishigi-juju-gatame
The armbar is one technique that is very popular and effective, it's the armbar. It's been used a lot in MMA and has been shown to be effective on larger people(it's easier to apply submissions on longer limbs). No matter how strong a person is, they won't be able to escape it with brute strength as a result of leverage and because the elbow gets locked in place. The longer the submission is locked on, the more damage that is done to the attacker, eventually breaking the elbow of the attacker if applied long enough. This submission can be applied from various positions. The more skilled people can apply it from a standing position(flying armbar).
2.) Small joint manipulations/Yubi Waza
Probably one of the most effective and simplest self defense techniques are small joint manipulations(finger locks). A lot of grappling arts teach this, including small circle Jiu Jitsu, Aikido and to a certain extent Brazilian Jiu Jitsu.
Hint: the pinky finger gives a person 50% of their hand strength, if a person's pinky is disabled their hand strength would be reduced by 50%.
3.) Toe hold/Ashi-Dori-garami
A submission used by mixed martial artists, it was used by Masakatsu Funaki to win his fight against the 6'11" Semmy Schilt. It's easier to apply this submission on larger opponents as a result of their longer limbs.
4) Gogoplata/kakato jime
A very popular Jiu Jitsu choke hold that gained fame when the professional wrestler the Undertaker started using it in his wrestling matches. In real life, it's a type of choke.
5.) Kimura/reverse Ude garami
A very popular submission that was made famous when Masahiko Kimura used it to beat Helio Gracie. Keep in mind there are many variations of this submission.
6.) Rear naked choke
One of the most popular and effective chokes is the rear naked choke, it's used in the military, martial arts competitions and self defense. It's very difficult to escape this hold.
7.) Wrist lock
There are many kinds of wrist locks you can use to defend yourself, some of them are able to force and attacker to drop their weapon. Some wristlocks can be used to takedown a aggressor and others can be used to throw a aggressor by using their own momentum against them.
8.) Throwing techniques/Nage Waza
Certain martial arts feature techniques where you throw your attacker, like in Judo. Keep in mind that most Throws don't rely on brute strength that's a common rookie mistake, the throws mostly rely on using the opponent's own momentum against them to throw them off balance.
9.) Pins
Yes, there are also pinning techniques you can use in self defense situations that don't heavily rely on brute strength. Aikido and Jiu Jitsu teach various kinds of pins. These are usually taught to police officers. Notice how in the picture he is using a wrist lock for the pin.
10.) Pressure points
There are pressure points throughout the human body, if a person knows where all those pressure points are, the person have temporarily impair a attackers abilities by targeting those parts.
11.) Disarming weapons
A very useful set of techniques a person should learn is how to take away a weapon from a attacker. Once a person takes away a weapon from a attacker, the attacker will immediately surrender since their weapon is now in the hands of the other person.
12.) Kubotan, Kakute or any pocket sized weapon
A Kubotan is a Jaapanese pocket/compact stick made out of metal that can be a effective self defense tool if you know how to use one. There are grappling and striking techniques that can be used with this. If you don't have a kubotan you can always improvise. A kakute is a spiked ring that is also a great self defense weapon if you know how to use them.
13.) Using the environment to your advantage
If you are outnumbered by a group of attackers, the wisest decision is to run, hide and call the police. However if you have no way of contacting the police or there is no help nearby you need to know how to use your environment to your advantage and how to divide your attackers. Some self defense classes teach you how to use your environment to your advantage(find loose pipes, large pieces of wood, stones, throw sand or dirt at their faces etc.
14.) Hojojutsu
The art of the rope provides self defense techniques used for restraining attackers. Of course you can use any type of strong strings if you don't have a rope, like shoe laces.
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