Symbiotic life forms: Capable of merging several different forms of life into something unique. Such as lichens on trees, which are a mix of fungi and algae. Their symbiotic relationship equally benefits both life forms and enables them to adapt and survive in environments that they would not be able to live in on their own.
Protozoan: Another of the official Kingdoms of life in Taxonomy, Protozoans are life forms that display both flora and fauna within them. Both the best features of plants and animals. They eat. They consume things. They also photosynthesize and poop. Sometimes at inconvenient moments.
Ephyphitic: Ephyphytes (air plants) are plants that exist outside of soil, preferring to cling to objects and derive all of their nutritional needs from the atmosphere itself. Spanish moss is an ephyphyte, think intelligent Spanish moss. This might fit in quite well as a concept for a species evolving in gaseous environments.
Fungal: Darkness is Void; Juffo-Wup is light. You are the non.
Energy: Light exists as both a particle and a waveform simultaneously. If energy is never truly lost, perhaps it exists in alternate dimensions that can impact ours. Could be a good lead in for multi-dimensional energy beings, spirit species or just a hyper-intelligent shade of blue.
DNA: DNA and RNA have been proven to exist, persist and survive independently of life forms. It exists in soil. It exists in water. It existists in air. It's a source of organically coded information which can, presumably, be read and learned from. How weird would it be to have a species that exists as nothing but a massive strand of DNA. DNA that could be inserted into an organelle to serve a purpose. RNA that could be inserted into a virus as a weapon, etc..
I could probably come up with a few more weird ideas but I hope a few of these helps spark your imagination.