It looks to me like a sempervivum stretching to get more light.

I agree, looks like light-starving sempervivum.

Most of your plants look very wet; I see you are in warm zone - is it raining a lot? Is it also humid? Are they planted in ground or containers? You need to provide good drainage for all of them wherever they are planted. Succulents will rot easily in mostly wet soil.

Hi Rina, I'm from Buenos Aires, Argentina. It has a humid subtropical climate. It rains about once a week in average, but often it doesn't rain for a couple of weeks (I'd say climate is changing, it's getting more dry...). I took the picture last Sunday morning and it was raining a bit. I purchased this tiny one last Saturday in a container, but I put it in ground over the same day. I have had other succulents (different kind of aloes, crassula multicava, crassula ovata, and portulacaria afra) in the gorund for a long time (~20 years) and they look quiet well to me. You can see in the picture my crassula ovata, and in the right-bottom corner a bit of one of my portulacaria afra. The tiny sempervivum is 1-meter away from the ones in the picture, it will have about 4 hours of direct sun a day. I hope it gets better soon (we are here in the beginning of the spring, the weather is great for getting better :). Thanks for your comment.

Juan

Np, I asked since Sempervivums do not care for too much heat and too much humidity (few other succulents don't). They will grow, but in your hot climate, I would make sure they are not in the hottest sun (usually around noon). Otherwise, they like good light. I have many, but I am in colder zone - my semps grow very well in full sun. They should not be so 'tall' - that seems to be etiolation, maybe it was kept in quite dark spot in the store. It is ok in ground or container. Just make sure there is no water pooling too much around - but you likely know that since you grow other succulents. In ground, I like to plant them on a mound, so they drain. They will grow in very little soil, you'll find them growing over the rocks. They should not have recurving leaves, better light and less water will help.

Here is different looking one, Sempervivum 'Oddity' I just got this spring, growing in the container:

Here is semp with similar leaves to yours; you can see it is very low to ground and has e number of 'chicks'. The leaves/rosette should not be curving down:

They are also monocarpic plants - ones the rosette blooms, it dies. In the meantime, it should produce many offsets (that's why the common name Hens&chicks), that can be left as they grow or separated and planted elsewhere.

Hope I am not telling you what you already know :)

Your Crassula ovata and portulacaria look very nice, growing them outdoors in good sun makes a difference.

I didn't know most of the things you said. I have had succulents but for a long time, but just because they came with the house when I got it. I took care of them, as well as of the other plants, but without knowledge they were actually succulents! Thanks again.