| HydroBox 1981170 | Indo Products Inc. | 9 Electronics11 Lighting | Pending | 2019 |
| HYDROBOOST 1582674 · TMA863572 | ELKAY MANUFACTURING COMPANY | 11 Lighting | Registered | 2013 |
| HYDROBOOST 2127912 | PENTAIR WATER POOL AND SPA, INC. | 7 Machines | Pending | 2021 |
| HYDROBIOX 2217986 · TMA1230723 | 11814192 Canada Inc. | 11 Lighting17 Rubber40 Treatment | Registered | 2024 |
| HYDROPORT 2180840 · TMA1211373 | Access Vascular, Inc. | 10 Medical | Registered | 2023 |
| HYDRABOLT 1369791 · TMA811745 | Innovative Mining Products (Pty) Ltd t/a New Concept Mining | 6 Metal | Registered | 2011 |
| HYDROBELT 1107810 · TMA601084 | Arnold Jäger Holding GmbH | 12 Vehicles28 Toys | Registered | 2004 |
| HYDROBOIL 0613175 · TMA387921 | ZIP HEATERS (AUSTRALIA) PTY LIMITED | 11 Lighting | Registered | 1991 |
| HYDROBLOC 0612830 · TMA383399 | an individual | 25 Clothing | Registered | 1991 |
| HydroBlok 2314355 | PELGAR INTERNATIONAL LTD | 5 Pharmaceuticals | Pending | 2024 |
| HydroBLU 2105097 · TMA1284236 | Güntner GmbH & Co. KG | 7 Machines9 Electronics11 Lighting | Registered | 2025 |
| Hydrobe 1950910 · TMA1267674 | Hydrobe Cooperation Inc. | 9 Electronics41 Education | Registered | 2024 |
| HYDROPON 1831553 · TMA1026217 | Axalta Coating Systems GmbH | 2 Paints | Registered | 2019 |
| HYDROFIT 1549497 · TMA887098 | OTIS ELEVATOR COMPANY | 7 Machines9 Electronics37 Construction | Registered | 2014 |
| HYDROB 1110345 · TMA621358 | CHEMISCHE FABRIK KREUSSLER & CO. GMBH LIMITED (A German limited liabilty company) | 1 Chemicals3 Cosmetics | Registered | 2004 |
| HYDROFOB 0290551 · TMA143988 | Everguard Coatings International Limited | 2 Paints6 Metal19 Building | Registered | 1966 |
| Hydrobe 2303643 | HYDROBE PTY LTD | 1 Chemicals40 Treatment42 Science | Pending | 2023 |
| HYDROPOD 2262664 | Owner not listed | 11 Lighting | Pending | 2023 |
| HYDRABOOTY 2216251 · TMA1245418 | HydraFacial LLC | 44 Medical | Registered | 2024 |
| HydroBlock 2025958 · TMA1275231 | CENTRE INTERDISCIPLINAIRE DE DÉVELOPPEMENT EN CARTOGRAPHIE DES OCÉANS (CIDCO) | 9 Electronics | Registered | 2024 |
| HYDROBOUND 2342443 | Boardriders IP Holdings, LLC | 25 Clothing | Pending | 2024 |
| HYDROVENT 2053674 · TMA1139790 · design | HYDROVENT LLC | 9 Electronics | Registered | 2022 |
| HYDROFLOW 1905440 · TMA1115517 | Hydropath Technology Ltd. | 9 Electronics11 Lighting | Registered | 2021 |
| HYDROPATH 1786320 · TMA974168 | Hydropath Technology Ltd. | 9 Electronics11 Lighting | Registered | 2017 |
| HYDROBLUE 1769194 · TMA1046022 | Owner not shown | 1 Chemicals | Registered | 2019 |