Ok, creative suggestions...
Play dough , make whatever he's into, animals, cars etc you can use cutters. Roll it, shape it
Paint, finger painting, hand painting, foot painting.
Messy play, gloop, jelly baff stuff, cooked and dyed pasta or rice, squidge it, pour it, mould it.
Outside, go to the park, jump in puddles, use chalk on the path, spray with old well washed out spray bottles, "paint" with water and big rollers and paintbrushes.
In the kitchen, let him help chop soft fruit, decorate cakes, bang on pots and pans.
Let what he enjoys take the lead. And through all activities you do talk to him. He will learn through an adult talking to him while engaging in normal play activities. Talk about everything, the colours, the textures, how things look, taste, sound, your emotions, his emotions. Narrate what you are doing if he is watching you, narrate what he is doing if you think he'd like that. Even if it doesn't seem like it immediately, he will absorb language. I heard recently little children need to hear a word used in its everyday context 2000 times before they themselves can understand it and use it. Sitting him down and "teaching" him words simply won't be as effective, it's actually more likely to turn him off learning.
Be enthusiastic in your interactions. I'm sure, like my DD, the reason he says oh no is because he's heard an adult say that in an emphatic way during a 'dramatic' situation and it made an impression on him. (My DD's nappy had burst all over her bed, and I said Oh no! when I discovered it I thank my lucky stars I didn't say something stronger! )