Google Maps in Leaflet Map

Streets

googleStreets = L.tileLayer('http://{s}.google.com/vt/lyrs=m&x={x}&y={y}&z={z}',{
    maxZoom: 20,
    subdomains:['mt0','mt1','mt2','mt3']
});

Hybrid:

googleHybrid = L.tileLayer('http://{s}.google.com/vt/lyrs=s,h&x={x}&y={y}&z={z}',{
    maxZoom: 20,
    subdomains:['mt0','mt1','mt2','mt3']
});

Satellite:

googleSat = L.tileLayer('http://{s}.google.com/vt/lyrs=s&x={x}&y={y}&z={z}',{
    maxZoom: 20,
    subdomains:['mt0','mt1','mt2','mt3']
});

Terrain

googleTerrain = L.tileLayer('http://{s}.google.com/vt/lyrs=p&x={x}&y={y}&z={z}',{
    maxZoom: 20,
    subdomains:['mt0','mt1','mt2','mt3']
});


Note the difference in the "lyrs" parameter in the URL:
Hybrid: s,h;
Satellite: s;
Streets: m;
Terrain: p;