Robert Burns is, without question, the most famous Scottish poet of all time, and one of the most well known poets of the later eighteenth century. His first published volume of poetry was called Poems, Written Chiefly in the Scottish Dialect (1786), and it is safe to say that Burns went a long way toward popularizing the use of Scottish words.
While a number of other writers followed Burns's lead in using their own, native dialect (chief among them the great poet and novelist Sir Walter Scott, who wrote in the generation after Burns), most of the poems you will encounter that contain "Scotticisms" will most likely be Burns poems.
So if you're reading a poem that sounds Scottish and contains some really funny-looking words, there's probably a 95% chance that it's a Burns poem. Words like "bonnie" and "lass," "gang" and "weel," are hallmarks of Burns's poetry; while other poets might sometimes drop in a similar word or two here and there, none do so with quite the same gusto as our man Burns.