Clauses of Reversal

But

Used to introduce a word or phrase that contrasts with what was said before: I got it wrong. It wasn't the red one but the blue one. His mother won't be there, but his father might.
However; despite this: I'd asked everybody but only two people came. By the end of the day we were tired but happy.
Used when you are saying sorry about sth: I'm sorry but I can't stay any longer.
Used to introduce a statement that shows that you are surprised or annoyed, or that you disagree: But that's not possible! "Here's the money I owe you. But that's not right - It was only $10."
Except: I had no choice but to sign the contract.
Used before repeating a word in order to emphasize it: Nothing, but nothing would make him change his mind.
(Literary) used to emphasize that sth is always true: She never passed her old home but she thought of the happy years she had spent there (= she always thought of them).

But for

• If it were not for: He would have played but for a knee injury.
• Except for: The square was empty but for a couple of cabs.

But then (again)

• However; on the other hand: He might agree. But then again he might have a completely different opinion.
• Used before a statement that explains or gives a reason for what has just been said: She speaks very good Italian. But then she did live in Rome for a year (= so it's not surprising).

You cannot / could not but... : (formal) used to show that everything else is impossible except the thing that you are saying: What could he do but forgive her? (= That was the only thing possible)
Except: apart from: We've had nothing but trouble with this car. I came last but one in the race (= I wasn't last but next to last). Take the first turning but one (= not the first one but the one after it).
Only: I don't think we'll manage it. Still, we can but try. There were a lot of famous people there: Tom Hanks and Julia Roberts, to name but two.

However

Used with an adjective or adverb to mean "to whatever degree": He wanted to take no risks, however small. She has the window open, however cold it is outside. However carefully I explained, she still didn't understand.
Whenever is used to emphasize how, meaning "in what way or manner", it is written as a separate word: How ever did you get here so quickly?
In whatever way: However you look at it, it's going to cost a lot.
Used to introduce a statement that contrasts with sth that has just been said: He was feeling bad. He went to work, however, and tried to concentrate. We thought the figures were correct. However, we have now discovered some errors.

Nevertheless

Despite sth that you have just mentioned. SYN nonetheless: There is little chance that we will succeed in changing the law. Nevertheless, it is important that we try. Our defeat was expected but it is disappointing nevertheless.

In Fact = In (actual) fact

Used to give extra details about sth that has just been mentioned: I used to live in France; in fact, not far from where you're going.
Used to emphasize a statement, especially one that is the opposite of what has just been mentioned: I thought the work would be difficult. In actual fact, it's very easy.
Is that a fact? (Informal) used to reply to a statement that you find interesting or surprising, or that you do not believe: "She says I'm one of the best students she's ever taught. Is that a fact?"

Even

Used to emphasize sth unexpected or surprising: He never even opened the letter (= so he certainly didn't read it). It was cold there even in summer (= so it must have been very cold in winter). Even a child can understand it (= so adults certainly can). She didn't even call to say she wasn't coming.
Used when you are comparing things, to make the comparison stronger: You know even less about it than I do. She's even more intelligent than her sister.
Used to introduce a more exact description of sb/sth: It's an unattractive building, ugly even.