A couple of variables.
First, quality of the bagel - the worse the bagel, the stronger the toppings. Doesn’t really apply to the OP, since these are their homemade ones, but with good bagels, less is absolutely more.
Personal preference is lox and cream cheese, though I love cream cheese with sliced fresh, quality tomatoes with a bit of smoked salt and red onion nearly as much.
Since we want to give more options, I’ll go with several others that I personally like, but may or may not match the tastes of others.
First, it’s a trope, but I do actually enjoy a ripe Hass avocado, lightly smashed with good salt, a dash of lemon juice, and a dozen grinds of black pepper smooshed down on top of a bagel.
Related, if you make homemade guac (Hass, fresh tomatoes, fresh cilantro, fresh onion, plenty of lime and salt, and several amazing fresh chili peppers) it is a thing of beauty on a good garlic or onion bagel.
And, equally different, some homemade hummus schmeered on top is lovely as well. In my case, made with chickpeas, garlic, onion, cilantro, lime and roasted green chiles, plus roasted garlic cloves, salt, and sprinkled with aleppo pepper or ground sumac berries.
Of course, if it’s a bagel that you’re enjoying in it’s own right, a smear of good, fresh butter can’t be beat. I like a salted Kerrygold or TJ Cultured butter, applied after the bagel has cooled a bit so that I get a mix of solid creamy butter and melted goodness sinking in.
BTW…
CURSE YOU!
You know I’m going to TJ’s in a few minutes to get some groceries. This is going to be rough…