Major taxonomies/classifications

Bartoc.org list of software for controlled vocabularies

Bartoc offers a list of software for controlled vocabularies that can be extended on GitHub

For Life Sciences

MeSH (Medical Subject Headings), controlled vocabulary for indexing articles in life sciences

Tools: MeSH Browser, PubMed

NCBI Taxonomy, classification of organisms

Tool: NCBI Taxonomy Browser

HUGO Gene Nomenclature, nomenclature for human genes

Tool: HGNC Database

UniProt Controlled Vocabulary, vocabulary for protein sequences and functions

Tool: UniProt Browser

For Health and Medicine

SNOMED CT (Systematized Nomenclature of Medicine – Clinical Terms), comprehensive, multilingual healthcare terminology

Tools: SNOMED CT Browser, IHTSDO

LOINC (Logical Observation Identifiers Names and Codes), standard vocabulary for clinical observations and lab results

Tool: LOINC Browser

ICD-10 (International Classification of Diseases, 10th Revision), codes for diseases, conditions, and health issues.

Tools: ICD-10 Browser, WHO

RxNorm, standard names for clinical drugs

Tool: RxNav Browser

UMLS (Unified Medical Language System), integrates biomedical vocabularies

Tool: UMLS Metathesaurus Browser

For Chemistry

IUPAC Nomenclature, system for naming chemical compounds

Tool: IUPAC Nomenclature Browser

CAS Registry, database of chemical substances

Tools: SciFinder, CAS Registry Browser

InChI (International Chemical Identifier), identifier for chemical substances

Tools: InChI Resolver, PubChem

PubChem, public database of chemical molecules

Tools: PubChem Search, NIH Entrez

For Environmental Science

AGROVOC, multilingual controlled vocabulary for agriculture, forestry, and environment

Tool: AGROVOC Browser

EPA Terminology Services, terminology for environmental protection and related subjects

Tool: EPA Terminology Browser

For Earth Sciences & Geospatial Data

CF Conventions (Climate and Forecast Metadata), metadata for climate and geospatial data

Tool: CF Standard Names Browser

GCMD Science Keywords (Global Change Master Directory), vocabulary for Earth science data

Tool: NASA Earth Science Data Browser

INSPIRE Directive, vocabulary for spatial data and metadata.

Tool: INSPIRE Geoportal

For Physics & Engineering

Physics Subject Headings (PhySH), vocabulary for physical sciences literature

Tool: PhySH Browser

CSD (Crystallography Structural Database), database of crystal structures

Tool: CSD System Browser

International Electrotechnical Vocabulary (IEV), standardized terms in electrical technologies

Tool: IEV Online Browser

Generalists

Dublin Core Metadata Initiative (DCMI), standard for metadata terms

Tool: DCMI Metadata Terms Browser

ISO 25964 Thesaurus Standard, thesaurus construction and controlled vocabulary standard

Tool: ISO Online Browsing Platform