just to second that Miso is really good.
I usually park my sardines on top of a whole wheat cracker spread with tomato pesto, but toast would work quite well too, I am sure.
Highly recommend, as well! I love Quince & Apple preserves with my favorite being the Fig and Black Tea.
Based on something I read here (maybe from you) I bought two jars on Amazon last year. It went very quickly, I’ll have to buy it again.
I don’t care for Marmite or Vegemite, but Bovril goes great on toast.
My favorite is a double cream with marmalade or lemon curd. If I’m having straight preserves then it has to be seedless lack raspberry.
And call me a “yuppie”, but avocado with toasted sesame seeds is just unbelievably good.
@Green_Wyvern, I think, I was the one disloyally advocating for the wholly British Gentleman’s Relish.
Sadly, local production of Peck’s is being discontinued soon, so I’ll have to source fish paste overseas. Or make my own…
My favorites aren’t anything near as fancy or exotic as some of you posters. My go-to spreads are:
Peanut butter - smooth or chunky
Butter w/sugar & cinnamon
Butter w/brown sugar
Butter w/raspberry jam or crabapple jam
Apple butter
On bagels, English muffins, or white bakery bread (bonus if the bakery bread comes unsliced and I can cut it into thick slices).
Bingo! I’ll order today.
I love miso soup, so I should try the paste on toast, etc.
Oh yeah… I’ve been doing it every morning and liking it. But start by spreading it very thin.
Indeed. I’ve been a huge fan of nutritional yeast powder since I discovered it as a condiment at the UCD dining facility in the early 90s. It works like turbo-charged MSG. As a side benefit, the brand I’ve been using lately (Anthony’s) turns your pee the color of Mountain Dew even though it has no color additives. Ok, I’m easily entertained.
I don’t often have breakfast…or toast…but:
Smooshed avocado topped with sliced hardboiled eggs and salt
Butter and marmalade or cherry preserves
Not really a toast topping, but I like bread soaked in egg and cooked a la French toast but seasoned with onion powder and salt… “egg bread”
My standard go-to with morning coffee is a plain bagel toasted on the stove top on a crepe pan, with butter and Boursin herb and garlic cheese:
Alternative is slices of toasted baguette with nothing but butter, but the bagel and Boursin is far better!
Another vote for blue cheese. I put it on rye bread. I had a wedge of Danish blue cheese in my refrigerator last month for this purpose. Then I got covid and completely lost my sense of smell for a couple weeks. I decided to save the remaining portion of the cheese until I could enjoy it again. Sadly, by the time my sense of smell returned, the remaining cheese was dried out and unusable. 
Miso and maple syrup butter is good. Sometimes with lots of black pepper or chili. I just whisk equal parts together.
Great as a glaze on just about anything baked or fried, too.
That is so yum.
However, I’ve got some mascarpone in the fridge that I have been putting on multigrain toast with a dusting of nutmeg. Today, I decided to try it with clove. I added too much clove, but yeah, good stuff.
When I got up this morning, I was a Marmite virgin. No more. I picked up a jar at World Market yesterday. They were out of Vegemite, or I would have gotten some of that, too.
This morning I did my buttered sourdough toast (I use unsalted Plugra exclusively) with Marmite and miso on separate sections. The Marmite taste was primarily salty, which is fine with me, as I had been in the habit of sprinkling a pinch of salt on my buttered toast anyway. The miso was also salty, but there was a bit of sweetness and also a sort of boozy, fermented overtone/taste. I liked both and will continue to use both.
One of us! Yay!
Yesterday I cracked open a jar of Salted maple caramel spread that had been gifted to us, and spread it on a toasted english muffin half with butter. OMG, had to force myself to stop after demolishing the 2nd half of the muffin too.