The Blood Pressure Sensor (BPS-BTA) does contain latex in the bulb and in the cuff. This means that the following parts also contain latex:
Blood Pressure Cuffs (CUFF-LG)
Blood Pressure Cuffs (CUFF-SM)
Blood Pressure Cuffs (CUFF-STD)

The Gas Pressure Sensor (GPS-BTA) itself does not contain latex, but both rubber stoppers that ship with it do.
#1 One-Hole Rubber Stopper (PS-STOP1)
#5 Two-Hole Rubber Stopper (PS-STOP5)

The Respiration Monitor Belt (RMB) contains latex in the bladder and in the bulb.

The following sensors do not contain latex:
Hand-Grip Heart Rate Monitor (HGH-BTA)
EKG Sensor (EKG-BTA) (EKG Electrodes (ELEC) do not contain latex either.)
CO₂ Gas Sensor (CO2-BTA)
Surface Temperature Sensor (STS-BTA)

The Reflex Hammer Accessory Kit (RFX-ACC) heads are made of silicone rubber.

If you need to know whether other Vernier products are latex-free, please contact Technical Support at 1-888-837-6437.

Related:
Does the LabQuest contain any latex?