PREFIX rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX vim4: <http://bipm.org/jcgm/vim4#>
PREFIX comp: <http://ua.be/sdo2l/vocabulary/component#>
PREFIX base: <http://ua.be/sdo2l/vocabulary/base#>

SELECT DISTINCT ?type
WHERE {
  ?entity a ?type .
  FILTER(?type = "uri")
}
