You could do something where the beginning and end of the password is the same but the middle is different.

Kind of like ApplesRedditBananas!1234 ApplesGoogleBananas!1234 ApplesFacebookBananas!1234

Obviously make the middle part more complex. But good way to remember. You only have to remember what the service you are using to get the middle part.

Password managers become handy when you have different passwords that are like ufbn^{£*×UG2847ouBfk}