A few questions:
1. If the USA passes on the Spanish colonies in 1898, do they have a go at them later?
2. Can the Spanish defeat the rebels in the Philippines and Cuba? Presumably they could in Cuba?
3. Does Spain sell the Philippines, and if so to who and are the other countries OK with this?
4. Does Spain holding on to more of its colonial empire butterfly away the Spanish Civil War?
The big one is obviously the Philippines, which is the most valuable of the group. If it somehow winds up in German hands, then it is targeted in World War I, probably by the French, but it means some French forces from elsewhere have to be diverted and there is the German Asiatic squadron to content with. But World War I is one of those events that can be butterflied by just about anything. If the Philippines become independent then that has an effect, of a colony successfully establishing its independence at that stage.
The possibility with the least butterflies is that Spain rallies and keeps its colonies, and Spain rallying also butterflies away the Spanish Civil War. If the Spanish Civil War still happens, I'm not sure if Cuba and the Philippines can be isolated. If it doesn't happen, you have some effects on World War 2 from no Spanish Civil War, and considerably more on twentieth century literature. And Spain's internal development changes.
Portugal kept its colonial empire until 1975, and that included a colony, East Timor, where the Japanese were operating, so its conceivable the Spain could hold these places until quite late in the twentieth century.
Things that might be butterflied away with no or different US involvement in Cuba include the Cuban Missile Crisis, the fall of Kruschev in the USSR, the JFK assassination, and pretty much IOTL South Florida. If Puerto Rico is not part of the US, no West Side Story and some changes to New York and Florida. A non-American Philippines affects the Vietnam War as well as World War 2.