Even though most people associate chameleons with only Madagascar, but they can be quite common (and are speciose) in the African forest, even on the edge in agricultural land. However, they are hard for a visitor's eye to find, so you may have to ask a local or go with a guide to find them.
Trioceros bitaeniatus, 'Side-striped Chameleon', (Rwenzori, Uganda). Central & eastern Africa.
Trioceros johnstoni, 'Rwenzori/Johnston's Three-horned Chameleon'. Restricted distribution, endemic to the higher altitude forests of the Albertine Rift in Uganda, DRC, Burundi and Rwanda.
Found on every continent except Australia and Antarctica, and absent from many islands.
Atheris nitschei, 'Great Lakes Bush Viper'. Large and long, up to 80 cm. Venomous, the bite causing haemorrhaging. Found in forests, forest edge, and wetlands at higher altitude around Albertine Rift region in eastern Africa.