Summarize:

The basic process for growing oyster mushrooms works for most mushroom species, but you will need to make adjustments. When you buy spawn, check the instructions or ask the seller for the following information so you can adjust your approach:  Preferred substrate (some species need a specially prepared compost) Ideal temperature during colonization Ideal temperature and humidity levels during fruiting (mushroom growth)Lion's mane, lingzhi, shiitake, enoki, and nameko mushrooms are all good choices for a second project, only a bit more difficult than oyster mushrooms. If mold or other contaminants take over your substrate, that batch of mushrooms will be unusable. Most mushroom species are not as resistant to contamination as oyster mushrooms are, so it pays to spend more effort keeping the area clean:  Wash your hands with antibacterial soap before handling any part of the operation. Take special care to pasteurize your substrate. If stovetop heating becomes impractical, look into a steam room or chemical treatment. Treating a compost substrate is complex, and may require help from an experienced grower. "Casing" is a layer of sterile material on top of a tray of substrate, usually a mixture of peat moss and ground limestone. Keep the casing moist so water gradually leaches through to the substrate, without making the substrate soggy.  Not all types of spawn need casing. Ask the seller or an experienced grower for advice. Do not ventilate the area until the tiny "pins" have appeared on the surface of the casing. Ventilating too early will trigger fruiting before the pins have broken through, growing mushrooms underneath the casing. Instead of buying spawn each time, you could grow your own from spores. This is a difficult and complicated task, but there are many free resources that can guide you. (Try contacting a mycological association in your area). One way to create a spawn culture is to make a spore print. Transfer the spores to a petri dish of agar using an inoculation loop, as described here (though you do not need to draw a T pattern). Repeat with several petri dishes, since some may fail to germinate. A mostly sterile environment is a necessity for making spawn. Before you begin, remove all rugs and curtains that could trap dust. Clean all surfaces with mild disinfectant, including the ceiling. Cover all openings with plastic sheeting, and make an "antechamber" at the entrance with a second layer of plastic.
Experiment with other mushroom varieties. Keep conditions clean. Cover the substrate with a casing. Make your own mushroom spawn.