Amazon.com: Structural Pipe Fitting, DIY Outdoor, Use Imagination -1-1/2"Tee-E Short, 3T-8, Aluminum Magnesium, Note: ID of fitting is 1.925, to take nominal 1-1/2" steel pipe which all have an OD of 1.9". :
Elbow, 1 1/2 in For Pipe Size, Structural Pipe Fitting - 54WJ97|3AE-8 - Grainger
Iron / Galvanized Fittings - Fittings - Ace Hardware
10 Sets 1 Inch 90 Degree Structural Pipe Connector 3 Way Metal Joint Chain Link Fence Clamp, Stainless Steel 201 Corner Fitting End Rails Clamps, Thickness 1.8mm - Amazon.com
922920-8 Structural Pipe Fitting: Support, 1 1/2 in For Pipe Size, For 1 7/8 in Actual Pipe Outer Dia, Pipe | Imperial Supplies
Maker Pipe | Structural Pipe Fittings for DIY Builders
Zoro Select Structural Pipe Fitting, Side Outlet Tee, Cast Iron, 1.5 in Pipe Size, 50000 lb Tensile Strength 4NXV4 | Zoro