I love so many things on toast...
Unsalted butter and either strawberry or apricot jam
Unsalted butter and honey
Unsalted butter and sugar (used to be my favourite as a kid)
Unsalted butter and Marmite
Unsalted butter, smoked salmon and cream cheese with chives
Smoked ham, emmenthal cheese and mustard
Roasted turkey breast, jarlsberg cheese, iceberg lettuce and mayo
Sometimes I blend tuna (in olive oil, strictly), mayo and capers (in coarse salt, -not- in brine) and then use it as a spread on toast. Yum.
Obviously I drain the tuna and wash the capers...
And Nutella, of course.