To me D seems a Sempervivum tectorum. You are right, that it is similar to F, which I think it is an other Sempervivum.
Some varieties of Sempervivum tectorum are found also on alpine level, so it is resistant to very cold temperatures. In general all the plant I see in this pot should be resistant to cold temperatures: Crassulaceae (the family of Sempervivum and Sedum) are succulent plants, but often seen in cold zones: no spikes, so not in a very dry environment (like deserts like environment), but they grow in dry places, so on stone and rocks: animals have other larger plants nearby (outside rocks). So we have such strange succulent on cold climate.
The form of leaves: flats ending with a large triangle and a small spike (for me) it is typical of some Sempervivum. Often such plants are nicer in vegetative state. Flowers are not so special.
Note: the name: "tectorum" means "of roofs". It was common in the past in the stony roofs.
A related family and genus are the Saxifragaceae (some time also succulent).
Note: to me, it seems a series of Sempervivum and Sedum that was sold by Aldi around 2013 - 2015.