'ph' is a digraph (two letters to make one sound), but it's not split.
'a with a magic-e' is a digraph as it's two letters to make one sound, but it's split over usually one consonant. It makes the vowel make its long sound.
'have' is not a great example, as the 'e' at the end, whilst silent, is there for other reasons (the fact that English words don't end in 'v').
'able' and 'table' aren't examples either, because the 'le' ending is different to a split digraph (it's called a consonantal-le syllable; it has similarities to the magic-e rule in some ways, because it also tends to make the vowel long if there is only one other consonant before it - compare 'bugle' and 'bubble'; but it's not the same thing).
'gate' and 'hate' are good examples. Try also: made, make, fade, crate, shape, snake, cane, same, etc. for the long-a sound. You can also find lots of example for split digraphs with long-i, and long-o, and some with long-u. Long-e is occasionally spelled with a split digraph in short (one-syllable) words, but it's not very common; it's more common at the end of long words, so examples there tend to be longer (athlete, compete, etc).