Modeling functions available in rstanarm
The model estimating functions are described in greater detail in their individual help pages and vignettes. Here we provide a very brief overview:
stan_lm, stan_aov, stan_biglmSimilar to lm or aov but with
  novel regularizing priors on the model parameters that are driven by prior
  beliefs about \(R^2\), the proportion of variance in the outcome
  attributable to the predictors in a linear model.
stan_glm, stan_glm.nbSimilar to glm but with various possible prior
 distributions for the coefficients and, if applicable, a prior distribution
 for any auxiliary parameter in a Generalized Linear Model (GLM) that is
 characterized by a family object (e.g. the shape
 parameter in Gamma models). It is also possible to estimate a negative
 binomial model in a similar way to the glm.nb function
 in the MASS package.
stan_glmer, stan_glmer.nb, stan_lmerSimilar to the glmer, glmer.nb and
  lmer functions in the lme4 package in that GLMs
  are augmented to have group-specific terms that deviate from the common
  coefficients according to a mean-zero multivariate normal distribution with
  a highly-structured but unknown covariance matrix (for which rstanarm
  introduces an innovative prior distribution). MCMC provides more
  appropriate estimates of uncertainty for models that consist of a mix of
  common and group-specific parameters.
stan_nlmerSimilar to nlmer in the lme4 package for 
  nonlinear "mixed-effects" models, but the group-specific coefficients 
  have flexible priors on their unknown covariance matrices.
stan_gamm4Similar to gamm4 in the gamm4 package, which
  augments a GLM (possibly with group-specific terms) with nonlinear smooth
  functions of the predictors to form a Generalized Additive Mixed Model
  (GAMM). Rather than calling glmer like
  gamm4 does, stan_gamm4 essentially calls
  stan_glmer, which avoids the optimization issues that often
  crop up with GAMMs and provides better estimates for the uncertainty of the
  parameter estimates.
stan_polrSimilar to polr in the MASS package in that it
  models an ordinal response, but the Bayesian model also implies a prior
  distribution on the unknown cutpoints. Can also be used to model binary
  outcomes, possibly while estimating an unknown exponent governing the
  probability of success.
stan_betaregSimilar to betareg in that it models an outcome that
  is a rate (proportion) but, rather than performing maximum likelihood
  estimation, full Bayesian estimation is performed by default, with
  customizable prior distributions for all parameters.
stan_clogitSimilar to clogit in that it models an binary outcome
   where the number of successes and failures is fixed within each stratum by
   the research design. There are some minor syntactical differences relative
   to clogit that allow stan_clogit to accept
   group-specific terms as in stan_glmer.
stan_mvmerA multivariate form of stan_glmer, whereby the user can
   specify one or more submodels each consisting of a GLM with group-specific 
   terms. If more than one submodel is specified (i.e. there is more than one
   outcome variable) then a dependence is induced by assuming that the
   group-specific terms for each grouping factor are correlated across submodels.
stan_jmEstimates shared parameter joint models for longitudinal and time-to-event (i.e. survival) data. The joint model can be univariate (i.e. one longitudinal outcome) or multivariate (i.e. more than one longitudinal outcome). A variety of parameterisations are available for linking the longitudinal and event processes (i.e. a variety of association structures).