I think you need to define ‘best 1v1 rush civ’ better. Just saying ‘Attack early’ isnt really enough.
If you want the quickest attack, then it is the 3 minute drush of Lithuania. No other civ can really match that speed.
If you mean what civ can feudal the quickest for feudal aggression, i will put my money on Mongols. They can do some 16-17 pop scout rushes, if you have lots of hunt.
To me Mayans for Archer rush (maybe Eagle too) and Magyars for Scout rush. If you are really love Man at Arms much, there is a Celts but pray god for non-micro-nerd opponent.
I forgot mention Incas for tower rush (poor Koreans) and Persians for TC drop.
I think that the Bulgarians deserve an honorable mention here with their free m@a upgrade, which saves a lot of food for even more infantry as soon as you hit Feudal age!
I am telling you - the only thing better than initiating a four m@a skirmish is doing a 6 m@a rush
.They will save 75 food from forging and 50 from the armor upgrade and their blacksmith works even faster. This mean that, even with a standar build order, the moment they attack you with maa they surely have these 2 upgrades, doing enough damage before archers enter into scene
Talking about archers, korean archer rush might be scary now.