streaming netflix etc

I have a Kindle Fire Stick that casts from your wifi.

My PS3 streams through wifi.

Roku

Pretty much any device with wifi and a browser can stream Netflix. Phones, laptops, tablets, desktops, etc...

My Sony media player connects to the web via Wi-Fi
It connects to the tv via HDMI cable
My laptop PC, like wise , HDMI cable to the tv
My Motorola android tablet does the same thing, connects to tv via HDMI cable

Roku, Apple TV, Amazon Fire TV, Roku-like devices from Netgear, Samsung and others will all feed a HDTV, as well as most BluRay players (all BluRay players have HDTV streaming apps, but not all have built in WiFi, about $10 price difference).

Some gaming boxes do the same job; my kids first started streaming through a Wii (but switched to a BluRay player) and I'm pretty sure the latest XBox and PlayStation boxes also have streaming apps.

Other stick-like devices include Roku Stick and Kindle Fire Stick.

What works for you will depend on what you want to stream. E.G. my sister's Apple TV will not stream content from Amazon Prime (although almost everything else is covered) and do not expect the Kindle Fire Stick and Amazon Fire TV to have apps for streaming content from the iTunes store. In addition to the Amazon vs Apple commercial issues, you need to make sure you get the right device if you want to stream the on-demand content from premium cable providers (e.g. HBO Go is not on every kind of streaming device). Google devices also do not do Amazon streams, and Amazon doesn't do HBO and some sports streams.

If you are not talking about feeding a TV, but just watching content, almost any Android or iOS Smart Phone or tablet will stream content from most sources to play on the phone or tablet, but not necessarily on the TV. In most cases the streamed content has to be picked up by what the device connected to the TV, with the relationship between iOS (and OS-X) devices and the Apple TV being an exception.

Google devices also do not do Amazon streams

IDK about devices branded Google

but Android will stream Amazon and Netflix

roku ps3 blueray players etc.. all connect to the TV via HDMI cable

the devices do NOT connect to the TV via wifi
they connect to your Internet connection via wifi