These are things you can do that will cost you money and will provide the creator with money directly. A general rule here is that the more you get for your money, the less the creator gets.
This is the most direct way to show your support of a creator and one which gives them the largest portion of your money. There are always fees involved with Paypal or other service providers of donations but on average the creator will receive around 90% of the funds that you send to them. Do not underestimate the impact direct donations can have - even a $1 donation helps immensely (a creator with only 1000 followers could survive on donations alone if each gave just $1 every month).
Direct Single Donations - Most live streamers have a page similar to this where you can directly send them a “donation” or “tip” with a message that will then appear on screen as they’re streaming. This can of course also be done off stream and most streamers will play the message at the start of their next stream.
Regular Monthly Support - Patreon has become a key income source for a lot of creators due to the main benefit of it being regular monthly support. Whilst one off donations can come and go, Patreon support is geared more towards giving a monthly contribution and in return you can get personalised perks as a thank you.
Crowdfunding - Sometimes creators will need to crowdfund a project to get it off the ground if it’s too expensive to invest in alone. These are always different and for various reasons but helping with this is helping the creator to do something they otherwise wouldn’t have been able to. Evaluate as and when needed.
Almost identical to live stream donations but exclusive to the Twitch platform, “cheering” uses “bits” as a form of currency with 100 bits sent equivalent to $1 in revenue for the streamer. Similar to donations a message will be displayed on screen during the stream and you get a special badge in the Twitch chat after cheering. Bits can be bought at various rates directly from Twitch, with the more you buy at once the less you pay per bit. The benefit of this is that the money that doesn’t go to the streamer goes into improving the platform rather than merely a payment processor, but the downside is that you’re paying a higher rate to give the streamer the same amount of money, especially outside the US. Whilst regular donations via PayPal result in the streamer getting around 90% of your money, cheering instead results in the streamer getting 60-80% of your money (depending on how many bits are bought at once and your location).
Another way to support that is exclusive to the Twitch platform, though other providers may offer similar programs, subscriptions are a monthly paid service with benefits specific to each streamer. For $5 per month you can subscribe to a specific Twitch channel and be granted benefits whilst watching, such as a message on screen each month (similar to donations), channel exclusive emotes for use in any stream chat across the site, exemption from watching ads when they’re played, and any other benefits a streamer may decide to have themselves such as sub-only game sessions. With this 50% of your money goes to the streamer with the other 50% going to Twitch. There are also $10 and $25 subscriber options but the added benefits for doing these instead significantly diminish. Nevertheless streamers get 60% of a $10 subscription and 70% of a $25 subscription.
Memberships on YouTube are that platforms answer to Twitch subscriptions, with a small amount of Patreon mixed in for good measure. Similarly to above, for $5 per month you can become a member of any YouTube channel and get emotes in live streams, a badge next to your name in streams and video comments, and any "perks" that may be offered by the creator. Each creator has this set up to their own tastes so each is worth a look to see if it's something you're interested in. With this method the creator will receive around 70% of your money.
The vast majority of larger creators and even a lot of small to mid sized creators will have some form of merchandise that you can purchase. Given the ease with which t-shirt stores can be opened now and customised it’s always worth checking the links of your favourite creators to see if they have something available you might like. Whether it’s items of clothing, mugs, keyrings, stickers, or phone cases that you want, it’s always worth having a browse to see if anything looks fun to own. With this you get a physical item that you want and you get to support the creator at the same time. Creators on average will get around 25% of your money when you buy some of their merchandise.
This is a follow on from the “Click Sponsored Links” section earlier and is certainly the least recommended thing to do if your sole purpose is to support the creator, however in those moments when you do see a product that a creator is advertising that you would like to buy, make sure you do it using their links and/or discount codes. Instead of doing a Google search and finding the item separately, using the (again usually tracked) links a creator has provided will let the advertiser know that you bought the item because of the creator they decided to advertise with. This not only helps the creator’s standing with the sponsor, but will also usually result in some commission from the sale going directly to the creator. It’s not high enough to be worthwhile buying items you don’t really need just to give your favourite creator some commission, but if it’s something you’re going to buy anyway you might as well go via them as opposed to Google. Creators usually make around 5-10% of the sale price of the item in commission.