electoral systems

No easy way unfortunately. I remember it like this:

Simple plurality: First past the post
Majoritarian: AV (used in House of Lords for by election of a hereditary peer, Labour and Lib dem leadership elections)
SV (Used in London mayor election, police and crime commissioners)

Proportional: Closed party list (European union parliament)
Single Transferable vote (Northern Ireland local government and assembly and used EU parliament)

Hybrid: Additional member system (Scottish Parliament, Greater London Assembly, Welsh assembly)
AV+ (Recommended by the Jenkins commission but never put in place, never been used!)

So in short

SP = FPTP
PR = CPL, STV
HYBRID = AMS, AV
MAJ. = AV, SV

this is all spot on but I wouldn't say AV is a hybrid, it's just a majoritarian system which simulates multiple rounds like a two round runoff system, but has it via just one ballot

AV is not a hybrid system, only AMS is

Hi there, AV and AV+ are two different systems! It was recommended by the Jenkins commission when it was set up in 1997 by New Labour. Look it up its a very interesting system.

oh, I think you forgot to put the "+" on the end of one of the AVs you mentioned then because you've got two "AV"s in your categories

No easy way unfortunately. I remember it like this:

Simple plurality: First past the post
Majoritarian: AV (used in House of Lords for by election of a hereditary peer, Labour and Lib dem leadership elections)
SV (Used in London mayor election, police and crime commissioners)

Proportional: Closed party list (European union parliament)
Single Transferable vote (Northern Ireland local government and assembly and used EU parliament)

Hybrid: Additional member system (Scottish Parliament, Greater London Assembly, Welsh assembly)
AV+ (Recommended by the Jenkins commission but never put in place, never been used!)

So in short

SP = FPTP
PR = CPL, STV
HYBRID = AMS, AV+
MAJ. = AV, SV