I'm no expert but I'd try 8.d4 or 8.Nc3 followed by d4.
Help with Muzio Gambit
It is a winning way to deal with the Muzio.
Yeah, that's what I thought. Most opening databases only show the Queen moving first.
I'll try d4 again and see what I can achieve.
Right, after 8. d4 Bxd4 9. Bxf4, black should have a harder time finding the right moves than white will even though black is theoretically ahead by a teensy bit.

i would not really say that black were theoretically ahead in this position. First of all, this is a wild position in which the outcome of the game will very much depend on the skill of the players.
White has sacrificed material for quick development and attack. So he will absolutely need to like playing for quick development and skilful attack if he chooses to try to play such an opening line.
Black will need a lot of good nerves and skilful defense in order to survive this, especially against a skilful attacking player.
I agree that some of the attacking and developing ideas for white will involve moves such as d2-d4 and Bxf4, possibly also even moves like Bxf7, even when this may be sacrificing a second piece!
By the way, a great expert on development and attack is IM David Pruess. His chess.com video lecture series on development is highly recommendable
Thanks for the comments, everyone! I feel that the Muzio Gambit appeals to my playstyle the most, so I should probably improve my Tactics now.
@ilmago: Unfortunately, I do not have a chess.com Premium atm. Is there perhaps a free Youtube video that can help me here?
...I play white, and I've been trying to find that one White move that is the reason this line is not in most databases, and proves that Black shouldn't have made this move. Care to enlighten me, Gambitking? :) (fitting name in this situation, too)
(and btw, I've been close to finding the move, but still haven't quite gotten there)

@ilmago: Unfortunately, I do not have a chess.com Premium atm. Is there perhaps a free Youtube video that can help me here?
I do not know of any free videos that have that kind of quality. And from the non-free teaching material on these and similar topics, according to my experience a chess.com premium membership is clearly among the best value per money I know of.
For some people who have loads of time and energy and work discipline it may be an option to spend their time collecting the free stuff they can find on the internet and try to put in enough work to organize this for themselves well enough to learn something from it.
But for almost all the people I know of, a much more normal and much better option is to spend their resources on buying some good teaching material, which classically can be some good books or in modern times can be a membership on a chess site with excellent teaching content, and thereby make much more progress with much less effort.
Mostly, free things are free for a reason, and of course, good teaching material can have some price for a good reason.
@ilmago: Unfortunately, I do not have a chess.com Premium atm. Is there perhaps a free Youtube video that can help me here?
I do not know of any free videos that have that kind of quality. And from the non-free teaching material on these and similar topics, according to my experience a chess.com premium membership is clearly one of the best value per money I know of.
For some people who have loads of time and energy and work discipline it may be an option to spend their time collecting the free stuff they can find on the internet and try to put in enough work to organize this for themselves well enough to learn something from it.
But for almost all the people I know of, a much more normal and much better option is to spend their resources on buying some good teaching material, which classically can be some good books or in modern times can be a membership on a chess site with excellent teaching content, and thereby make much more progress with much less effort.
Mostly, free things are free for a reason, and of course, good teaching material can have some price for a good reason.
Well, I am a young amateur player. If I had the ability to pay for a membership or buy resources, I would do it in a heartbeat. But for now, I must resort to free resources. :) However, I am quite jealous of the quality of the chess.com videos.
I agree with the people who have said they don't know who would play this as black to begin with. I usually play a line as black that goes like the following if it goes my way (hope I remember it correctly)

Gambitking, you are not seriously comparing your best friends to free stuff one can find on the internet and calling both "simple life", are you?
For learning something, it may often not be enough to try to do it somehow for free on the internet, you just need a good teacher and a good book.
If you wish to turn this into a thread about good friends, then these good friends will appreciate it if you do not waste too much time searching for free stuff on the internet, because you will have more time to share with your friends if you are getting your learning done in an effective way.

I observe that you have not been reading what has been written above, Gambitking. I have not recommended books for learning this specific gambit line. I have recommended good learning material that will be able to teach a player about the fundamentals that will be needed when playing such a gambit position. In order to play this position with white, a good understanding of development and attack is essential.
seems like if the queen is on h4 (or anywhere away from the f pawn) then Bxf7 is very much for real. So d4, Bxf4, Bxf7 seems like a good a plan.

Of course it is nice to analyze with friends who are prepared to share their ideas with you. However, when it comes down to playing games, knowing lines will not be sufficient. You will need to know about development and attack, and you will need the practical strength in order to compete in that type of position in a real game.
I do not advise the OP to learn many specific lines for this position at the strength he is at presently. My recommendation for him is to learn about development and attack. Much of this will be done by analyzing and playing such positions, but much of the most important fundamentals for this are recommended to be learned from a really good teacher.
//edit: I see, Gambitking, how proud you are of having a special theory source, and I see that for you this thread is about "speaking louder" and about wishing to have the last word. If that makes you happy, may you have had it. Have a nice day.
Okay, so I'm an amateur player who is trying to master the Muzio Gambit. I've got most lines memorized, except for the following: