There are many antibodies available from many manufacturers. Do you have any specific manufacturer that you would prefer ? Price range ? Other usage than immunostaining ?
For example here is a list of some available Ab at invitrogen (https://www.thermofisher.com/antibody/primary/target/ha%20tag/filter/host/Goat~Chicken)
HA-Tag Antibody (153) is a rat monoclonal IgG2a, cited in 18 publications, provided at 200 µg/ml
raised against the HA peptide derived from influenza hemagglutinin
recommended for detection of proteins containing the HA tag by WB, IP, IF and FCM
available conjugated to Alexa Fluor® 488, Alexa Fluor® 546 or Alexa Fluor® 647 for WB (RGB), IF, IHC(P) and FCM, and for use with RGB fluorescent imaging systems, such as iBright™ FL1000, FluorChem™, Typhoon, Azure and other comparable systems