Howdy. The first two seem to be new world desert plants; the second may be a variety of prickly pear. The 3rd is either colocasia or alocasia. #4 looks like a kind of bromeliad, but I can't be sure. I'll post more later; gotta run. Thanks in advance.
# 4 Resembles Neoregelia schultsiana. http://plantsarethestrangestpeople.blogspot.com/2008/10/dorothy-gale-neoregelia-fireball.html Turns out that may not be a valid name. HTH Chris
#3 looks more like a Xanthosoma to me... Could be a big Alocasia, but the lack of fusion in the posterior lobes makes me think otherwise...
Lorax, I honestly can't distinguish between the xanthosomas I found on the web and what I recognize as alocasia. Can you explain the difference? Here are some more.
Urglefloggah - Xanthosomas generally have separate posterior lobes, rather than ones that are fused together at the base, giving the leaves a characteristic arrowhead shape; Alocasia (at least the bulk of the species I'm familiar with) are at least partially fused towards the junction of the petiole and the leaf, giving them a characteristic heart shape. The plant in my attachment is a Xanthosoma commonly known in Ecuador as "Pelma" and grown as a food crop alongside Alocasia; compare using GIS to Alocasia to see what I'm talking about.
That leaf is about two inches shorter than me, which makes it about 5'10" long. Oh, and Urglefloggah - the fourth plant in your second posting is Colocasia esculenta - Taro root. Number 2 is likely an Aloe, but not a species I'm familiar with; Number 3 is likely a Haworthia of some description. If you repost them to the Cacti and Succulents forum, you'll likely get specific answers from the cactus and succulent experts.