15 New Validity Index for Fuzzy Clustering.
Partition Coefficient, Partition Entropy, Fukuyama and Sugeno, Xie and Beni, Kwon, Gath and Geva, Wu and Yang, Zhang et al., Rezaee, Fazel Zarandi et al. and Askari et al. (Title: A new validity index for fuzzy-possibilistic c-means clustering)

17 New Validity Index for Hard Clustering.
Dunn Index (DI), Davies-Bouldin Index (DB), Silhouette Index (SI), Rand Index (RI), Adjusted Rand Index (ARI), Jaccard Index (JI), F-measure (Fmea), Mutual Information (MI), Normaloized Mutual Information (NMI), Rogers-Tanimoto Index (RTI), Variation of Information (VI), Geometric Accuracy (GA), Overlapping Normalized Mutual Information (ONMI), Purity Index (PI), and Completeness Index (CI). (Title: Clustering Algorithms in an Educational Context: An Automatic Comparative Approach)

Six Accuracy Measures.
Mean Absolute Error (MAE), MSE Mean Squared Error (MSE), RMSE Root Mean Squared Error (RMSE), Mean Absolute Percentage Error (MAPE), Normalized Mean Squared Error (NMSE), and relative Standard Deviation (rSTD) (Title: Practical Numerical Math Functions (pracma))

Three Accuracy Measures. Mean Absolute Error (MAE), MSE Mean Squared Error (MSE), Coefition of Variation of RMSE Root Mean Squared Error (CV RMSE) (Title : Evaluation of the Impact of Gap Filling Technology in Precipitation Series on the Estimation of Climate Trends, the Case of the Souss Massa Watershed)