Another well known YouTube channel of relevance to worldbuilding comes from Biblaridion. It covers constructed languages (conlangs), speculative evolution and other topics. I can definitely recommend subscribing to this channel.
I’m not going to discuss conlangs further at this point as they are not really my thing. I’m a scientist not a linguist! However, if you are interested in that sort of thing I’ve been informed they are worth watching.
In contrast, I have watched the ongoing Alien Biospheres series and they are very informative for speculative evolution purposes. The episodes cover the evolution of life on the planet Tira. This includes a phylogenetic tree that expands in every episode as life adapts to various changes on the planet. At present there are 12 episodes which cover the following subjects:
- Early life and body plans
- Cladistics and ecology
- The invasion of land
- Terrestrial diversity and ecology
- The open plains
- Return to the water
- Adaptations to climate
- Tropical rainforest
- Sociality and cooperation
On a different subject, in November last year Biblaridion released a video introducing a fantasy world called Refugium. This world is a flat surface illuminated by static sun floating 1000 km above the surface. This produces a lit circular region surrounded by gloom. The equivalent of night is produced by a circle of five moons which orbit the sun and cast shadows across some of the lit region.
I find this particularly relevant because it is an example of a fantasy world that is not possible in real life. Exploring the implications of such an arrangement is an interesting task. What other “impossible” worlds can be imagined?