There are several tools available for RNA classification, each with its own strengths and limitations. Here are some commonly used tools:

1. Infernal: Infernal is a popular tool for RNA classification that uses a covariance model approach to identify RNA homologs. It is particularly useful for identifying non-coding RNA (ncRNA) sequences.

2. Rfam: Rfam is a database of RNA families and their corresponding covariance models. It is based on Infernal and provides a comprehensive resource for RNA classification.

3. RNAcode: RNAcode is a machine learning-based tool that uses a support vector machine (SVM) algorithm to classify RNA sequences. It is particularly useful for identifying small functional RNA molecules.

4. RNAmmer: RNAmmer is a tool for predicting rRNA genes in genomic sequences. It uses a combination of HMM-based and BLAST-based approaches to identify rRNA sequences.

5. tRNAscan-SE: tRNAscan-SE is a tool for identifying tRNA genes in genomic sequences. It uses a combination of HMM-based and comparative sequence analysis approaches to predict tRNA genes.

These tools can be used individually or in combination to achieve the best possible classification of RNA sequences.