If you search online you will find websites with some information. However, there are so many viewpoints in Lisbon that it would be difficult to list them all.
I believe this is not a problem, once you arrive in Lisbon you will find some great vantage points by yourself. Just explore the city and try to get to top floors, or just start walking uphill (they call it the city of 7 hills). For example, the 4 photos you just shared are all from the same area in Lisbon, but from different angles. There's hundreds of great viewpoints from that area, just don't forget to bring your camera.
Here's some hidden gems that you won't find in websites:
- 38°42'47.0"N 9°08'11.3"W - on the top floor of the Pollux store there is a small coffee shop with an amazing view
- 38°42'44.1"N 9°08'05.0"W - on the top floor of this building there is a restaurant called Zambeze with a great balcony next to it, an outstanding view. On the ground floor there is a supermarket with an elevator you can use to go up, or you can just walk around the building, although the street is quite steep.
As you can understand, you just need to explore and you will have fun. There are hundreds of small corners and streets in Lisbon that you will only find if you go there by yourself, don't rely too much on guides.
PS: There are outstanding viewpoints in Sintra, just catch the train, it's a magical place.